Students can get 1/2 off anything from ePocrates with a student code. The pdf containing the details is too large to upload here, but email me and I'll forward it to you (I'm inbetween systems, so posting it on the web will be a hassle). [email protected]
It's not free for everyone, but your school may have a subscription to mobileMICROMEDEX, which is much like ePocrates. I get the software and free updates through a license owned by my school's medical library. It runs just fine on the Axim X5 with plenty of memory to spare.