When we all say "drill motor" yes that's the one we mean. But we usually refer to it with the gearbox attatched (longer brown box same bag) as the motor is almost never used by itself. The gearbox has a high and low speed shift selector. For a rookie team, I would recomend locking it in place and not shifting during the match. Check out these links
Gear Ratios
FIRST Drill Motor Gearbox Exploded View
There is also the option of using the Chiaphua (Atwood, CIM) motors which have a coupler provided but no mount.
The rpms and gear reductions for the drill motor can be found in the Kit section of the Robot Rules. The Chiaphua motor specs have been posted as an attatchment in another thread here on Chief Delphi.
If you want to use all four motors. Match their free (no load) top speeds. Your rpm will be th number you match them at. The number you will actually get in performance will be a little lower so design with that in mind. You will get the torque of both motors combined plus whatever you get through a reduction.
Also, look thorugh the white papers on this site as they are very helpful. Just remember, I would not recomend shifting for a rookie team. (This is our third year and we are still too scared to attempt it)
Hope this helps,
sanddrag