if you search tethering, you will find a lot of information. You can do it, but the newest plans from sprint usually prohibit tethering unless you have a PAM plan added to it.
Please please please search well before you post. I
just answered another question like this one not 10 mintues ago and i originally found my answer on the touch pro essentials thread back in december...
http://forum.ppcgeeks.com/showthread.php?t=59168