The sources for the frequencies are as follows:
Radio Reference's Nassau County Database
Scanner Master NY Metro/NNJ Communication Guide - 7th ed.


There are also two maps you can download
Google Earth, and an Adobe PDF

Nassau County Police Frequencies

Channel	Frequency	ID Tag	PL/DPL	Mode
1	478.9125	NCPD Precincts 3 / 6	179.9	FM
2	478.5625	NCPD County Wide Tac	179.9	FM
3	477.3875	NCPD Precincts 2 / 8	179.9	FM
4	477.2375	F-4 Details	179.9	FM
5	478.5375	NCPD Precincts 1 / 7	179.9	FM
6	477.2125	NCPD Precincts 4 / 5	179.9	FM
7	478.7125	Detectives BSO ESB EAB	179.9	FM
8	477.2625	Highway and ESU	179.9	FM
9	478.9375	Surveillance Rptr	179.9	FM
10	478.7375	Tactical (Tac-10)	179.9	FM
11	478.9375	Surveillance Simplex	179.9	FM
12	478.7375	Tactical Simplex	179.9	FM
13	470.8625	NYPD Countywide	151.4	FM
14	477.2875	Aviation / Marine Bureaus	179.9	FM
	477.1875	Future Use	179.9	FM
	478.5125	Shop Freq	179.9	FM
	477.2375	NARCO-1	186.2	FM
	470.8125	Highway Patrol Mutual Aid to NYPD Traffic	123.0	FM
	470.8375	Highway Patrol Mutual Aid to NYPD	136.5	FM
	153.740	Old Freq-8 Air and Marine Bureaus	None	FM
	123.45	Air Bureau Company Freq	None	AM
	123.00	Air-to-Air (public use)	None	AM
	154.115	Auxiliary Police High Band	100.0	FM
	39.400	Auxiliary Police Low Band		FM
	37.140	Auxiliary Police
	39.46	Statewide Low Band Intersystem

Village Police Frequency List

Frequency	ID Tag	PL/DPL
461.800	CW Post Public Safety
463.475	CW Post Public Safety
155.190	Centre Island Police
154.040	East Hills Code Enforcement (Security)	210.7
463.850	Elmont Civilian Patrol
155.775	Floral Park PD F-1 (Dispatch / Ops)	131.8
156.210	Floral Park PD F-2 (Village Inter System)	131.8
155.370	Floral Park PD F-3 (Statewide Police Inter-Agency)
155.475	Floral Park PD F-4 (National Police Inter-Agency)
155.055	Floarl Park Police
155.925	Floral Park Police
155.625	Floral Park "Lost Community Civilian Patrol"
464.950	Franklyn Square Civilian Patrol
460.2875	Freeport Police Dispatch	179.9
460.0875	Freeport Police - Ch 3
460.4625	Freeport Police
155.430	Garden City Police Dispatch/Ops	186.2
153.860	Glen Cove Police Dispatch	203.5
155.370	Glen Cove PD "Statewide"
154.860	Great Neck Estates PD	156.7
155.370	Great Neck Estates PD "Statewide"
156.210	Great Neck Estates "Intersystem"	131.8
155.010	Hempstead Town Public Safety	107.2
154.710	Hempstead Vlg Police F-1	146.2
155.970	Hempstead Vlg Police F-2	146.2
155.955	Hempstead Vlg Police
464.525	Hofstra Public Safety	466
154.860	Kensington Vlg Police Dispatch	156.7
155.610	Kensington Village Police	156.7
156.210	Kensington Village Police
156.370	Kensington Village Police
155.610	Kings Point Police	156.7
156.210	Kings Point PD Intersystem	131.8
155.370	Kings Point PD "Statewide"
155.040	Kings Point PD F-8	156.7
155.610	Lake Success PD	156.7
155.210	Lake Success PD Intersystem	131.8
155.310	Lake Success PD "Statewide"
154.890	Lake Success PD	156.7
155.475	Lake Success PD F-5
154.025	Lake Success PD F-7
155.145	Lake Success PD F-8	156.7
154.740	Long Beach PD Dispatch / Ops	703
155.370	Long Beach PD "Statewide"
156.210	Long Beach PD "Instersystem"	131.8
460.3875	Long Beach Police
465.3875	Long Beach Police
155.640	Lynbrook Police Dispatch	82.5
159.015	Lynbrook Police
39.54	Lynbrook Police
39.660	Lynbrook Police
155.130	Malverne Police	131.8
474.350	Malverne Police
461.325	New Hyde Park Civilian Patrol
155.190	Old Brookville PD	203.5
155.370	Old Brookville PD "Intersystem"
156.210	Old Brookville PD "Village Aid"	131.8
155.475	Old Brookville PD "National"
155.535	Old Westbury PD F-1	203.5
155.190	Old Westbury PD Mutual Aid	203.5
155.370	Old Westbury PD "Intersystem"
156.210	Old Westbury PD "Village Aid"	131.8
155.190	Oyster Bay Cove Police Dispatch	203.5
154.785	Oyster Bay Cove Police
155.370	Oyster Bay Cove PD "Intersystem"
155.610	Pt Washington Police	156.7
155.370	Pt Washington Police
156.210	Pt Washington Police "Village Aid"	131.8
154.770	Rockville Centre Police Dispatch	131.8
155.370	Rockville Centre PD "Intersystem"
156.210	Rockville Centre PD "County Aid"	131.8
155.610	Sands Point PD Dispatch	156.7
155.370	Sands Point PD "Intersystem"
156.210	Sands Point PD "County Aid"	131.8
155.475	Sands Point PD "National Aid"
155.715	Sands Point PD F-8 (Public Works)
464.375	Valley Stream Civilian Patrol
469.525	Valley Stream Civilian Patrol

Nassau County Public Safety Talk Groups

Department	Talk Group	Description
Emergency Management
	06-071	Main
	06-072	Tac 1
	09-100	Fleet
County Police
	06-141	Auxiliary Police Main 1 (NASCAP)
	06-142	Auxiliary Police Main 2 (NASCAP)
	08-061	Nassau County PD
	09-101	NCPD Demo 1
	09-102	NCPD Demo 2
	09-103	NCPD Demo 3
	09-104	NCPD Demo 4
	09-105	NCPD Demo 5
District Attorney
	08-062	DA Contact
	09-041	DA Squad Tac-1
	09-042	DA Squad Tac-2
	09-043	DA Squad Tac-3
	09-044	DA Squad Tac-4
	09-045	DA Tactical
	09-051	DA Executive
	09-052	DA Supervisory
	09-053	DA General
	09-061	DA Investigative 1
	09-062	DA Investigative 2
	09-063	DA Investigative 3
	09-064	DA Investigative 4
	09-071	DA Process Servers 1
	09-072	DA Process Servers 2
Probationary Department
	08-011	Probation Main
	08-012	Probation Administrative 1
	08-013	Probation Administrative 2
	08-014	Probation Administration Division
	08-015	Probation Warrents
	08-016	Probation Warrents Tac-A
	08-017	Probation Warrents Tac-B
	08-021	Probation Tac-1
	08-022	Probation Tac-2
	08-023	Probation Administrative Tac
	08-025	Probation Training Tac
	08-031	Probation Director
	08-032	Probation Chief Deputy
	08-041	Probation Criminal Criminal Division
	08-042	Probation Criminal Criminal Tac
	08-043	Probation Academy
	08-051	Probation Familiy Court Division
	08-052	Probation Family Court Tac
	08-053	Probation Family Court Records
Sheriff's Department
	04-005	Sheriff Tac-1
	04-011	Sheriff Dispatch
	04-012	Jail Security South
	04-013	Jail Security North
	04-014	Prisoner Transport
	04-015	Jail Administrative
	04-016	Jail Maintenance and Kitchen
	04-017	Superior Officer
	04-021	SBI CIU VG
	04-022	CERT
	04-023	SBI IAU VG
	04-024	Tac-4
	04-025	Tac-5
	04-026	Planning
	04-027	Deputy Front
	04-030	Deputy Familiy
	04-032	Deputy Front or Evictions
	04-033	Deputy Family Court or Warrents
	04-034	Tac-1
	04-035	Tac-2
	04-036	Nassau County Link
	04-037	MDT
	04-040	Com-Link
	04-041	Sniper / SWAT - or MDT
	04-042	Com Link
	04-044	Sniper
	08-061	County PD
Village Police Departments
	03-063	Kings Point PD
	04-051	Freeport PD
	04-071	Lake Success PD Patrol
	04-072	Lake Success PD Supervisor
	04-081	Sands Point PD Patrol
	04-082	Sands Point PD Tac-1
	04-083	Port Washington PD Patrol 1
	04-091	Port Washington PD Patrol 2
	04-092	Port Washington PD Tactical
	04-093	Port Washington PD Detective
	04-094	Port Washington PD Narcotics
	04-095	Port Washington PD Admin
	04-096	Port Washington PD Inter Agency
	09-081	Village of Old Westbury Police Main
	09-082	Village of Old Westbury Police Tac 1
	09-083	Village of Old Westbury Police Tac 2

I will save this as a CSV file ready to import into Excel, or Scanner PC Software at a later date