I would guess that pretty much any scan tool could "scan" an obd2 car.
Sears has a decent selection of these. If all you want to do is see
what codes your car has, even the cheapest should work. I should warn
you, though, a lot of those things are fine for scanning "common" cars
like GM, Ford, etc., but BMW could be a different story. This is true
especially if you get one that reads some data that the sensors send
out. Even then, as long as you're using the generic obd2 mode, you
should be fine. 1996 was the first year that obd2 was required on all
cars in US, but I've read that some manufacturers still weren't fully
complied. Make sure your car has the proper hook-up.

You might look at http://www.scantool.net/forum/ - there's quite a bit
of info there.

G