General requirements
Mac computer with an Intel, PowerPC G5, or PowerPC G4 (867MHz or faster) processor
512MB of memory
DVD drive for installation
9GB of available disk space
Took me 20 seconds to find that...
Obviously if you have the base specs it isn't going to run as fast as Mac Pro, however if you have mid range specs, you should be ok.
EDIT: I will agree with everyone else you should upgrade the ram, get 1GB, you can use any brand of ram, just make sure you get the right speed, check in the System Profile to see what speed your is, then go and purchase some, I would suggest Crucial.com, I swear by them. They also have a dedicated mac section too.