Well, Rob, I have first hand knowledge about the Mass. State Police
communications and can give you the frequencies for MA. but can only
give you the FCC listed frequencies for NH and ME.

Mass. State Police

42.44  Channel 1  Statewide Emergency/Tactical Operations
42.34  Channel 2  Troop "A" operations / car-to-car Western Ma
42.4   Channel 3  Troop "C" operations
42.50  Channel 4  Troop "D" operations / car-to-car Western Ma
42.54  Channel 5  Station "h" sometimes Troop "A"
42.46  Channel 6  Troop "B" operations / Car-to-Car Eastern Ma
42.42  Channel 7  Team "55" / radar operations *must have*
44.74  Channel 8  Air Wing

154.92 Cruiser repeater (325 cruisers have these) Great to 
       see if cruiser is close.  Range approx. .5-1 mile

465.0125R  Repeats Channel 4.  Only in Quincy, Hingham, area

159.03R  Troop "E" Operations (All turnpike patrols)
156.03  Input to turnpike repeater

Notes:

Troop "B" - From western border to a Springfield area
Troop "C" - From Springfield area east to Approx. 495 area
Troop "A" - 495 to Boston and north to NH border
Troop "D" - South shore from Boston to Cape along RI border
Troop "E" - refer to mile markers to identify location along
	    turnpike.  Mile markers on the median start with 
	    MM1 in West Stockbridge and MM134 in Boston.

Incidentally, try 453.7125.  Its a road monitoring system which contains 
information about windspeed, direction, humidity, temp, and chemicals
at bridges.  Located at Westfield River Bridge, Chicopee River, and 
Quabog river.  Around Interchange 3 and 5, I think.  It would be 
interesting to see if it is digital or a computer voice, etc. That
would be appreciated.

Here is a list of NH and ME freq.  I don't know much about them though.

Channel 	Transmitter City

New Hampshire
F-1 44.94	Manchester
F-2 44.82	Epping
F-3 45.26	Epping
F-4 45.3	Epping
F-5 45.22	Keene / Troop C
F-6 45.46	Keene / Troop E
F-7 45.18	Aircraft / Car to Car
    44.82	Car-to-Car
    44.94	Sargents Prchs / Troops B+D
    45.30	Bow / Troop A
    45.18	Aircraft Patrol
    45.26	Carroll / Troop F

Maine

42.12
42.14
154.65 State Police Zone 2
154.665 State Police Zone 1 Scarborough, Bangor, Portland, Orono Trans.
154.695 State Police Car-to-Car
154.71 Emergency
154.905 Zone 3  Orono, Patten, Topsfield Transmitters
154.935 State Police Radar
155.43 Police Net 7 Kittery, Scarborough, S Portland
155.445 SP zone 1 
155.505 SP zone 2
155.85  SP zone 3

That'll do it for me.  I can vouch for the MA freqs but not ME & NH.