I have a gear ratio calculator with a good selection of transmissions and transfer cases. It calculates overall ratios, vehicle speeds at various RPMs and RPMs at various speeds. The non 4x4 crowd can use it but they won't care about the low range stuff.

http://www.grimmjeeper.com/gears.html

If there's a transmission or transfer case you want me to add, just let me know what it is and the gear ratios and I'll add it.