How do i share files between win xp pro computer and linux red hat 9.0 computer?

There is actually a multitude of ways...
If you want to use the normal network neighborhood stuff with windows, Samba would be the best way... http://www.samba.org
I have never set up samba personally...
Another way is to set up an FTP or SFTP server...if you run OpenSSH with your RedHat, there's a program called putty that will allow you to do it...
Other than that, you can run a webserver if you intend to have one as a server...but that's probably not the best way.

I'd check into Samba myself...it's supposed to seamlessly work with the windows file sharing

Samba is the way to go, you'll probably find it as a package for your distro. Setting up is not that hard.

SFTP is much easier to set up (it's usually enabled by default or you might have to do "sudo service sshd start") if you just need to use it from time to time, but if you need to transfer files on a regular basis samba is probably the way to go.