As far as I recall there are a few NFS clients for Windows, but I have to ask, are you sure you need this? RedHat comes with SAMBA included. SAMBA is a Linux/Unix implementation of Windows' own file-sharing system. You'll probably find that it is much simpler and cheaper to just start/configure the SAMBA that you have already on the Linux box, and then you can access it from any Windows machine with no extra software.
Thank you, Frank, Yes, I know that Samba comes with Linux 9. I am yet to learn how to configure it. I did not know that we need no extra software on the Windows box to access the Samba file server. Actually, my boss wants me to set up such a Samba file server. Can you tell me what are the cool benefits of using Linux + Samba as the file server instead of Windows NT?