I would say if you enter them from the living area not the garage and they have closets count them as bedrooms.

If they have the same heating or air conditioning as the rest of the house and they are as insulated as the rest of the house, you bet they are bedrooms in my book.  Also the closets as Bob mentioned and probably a window on each room.

You have it all in the two comments made. Closets, HVAC, and enter throught the main house. Bedrooms. (Period)

I agree they are bedrooms.  I estimate the value on an over the garage bedroom the same as I do a basement bedroom when I do a CMA.  

Ditto.  Closets, a/c and heat, enter from inside home = square feet to count in your CMA.  Actually in the La. market we refer to them as FROG (free room over garage) and are always counted in total living area if they meet above requirements.

they are bedrooms....but take them at a decreased value if the cieling of the garage wasnt insulated properly....which in 95% of homes it wasnt....also look for baseboard heaters in this room, even if its a forced air home...this is a good indication that in the winter it gets damn cold in that room.

there are other issues, but i cant give them all away....i know all this cause one of the rooms in my house is right above the garage and its used as an ensuite retreat to the master...

you really need to check out how well the room is built, as the builder sometimes offers these rooms as ad ons and not part of the original plans. so they tend to do a sloppy job thinking no one will notice.