Example from the forum modified with this option:
Don't worry about the client section of the writeup, you only want a server.
Then on your mac (if you have snow leopard), open Disk utility, go to file->NFS mounts, click the plus, add the server as "nfs://server.local/path/to/files"
The next blank is where you want it mounted on your Mac, I usually put "/network/_whatever_you_want_here_" because it will show up in the 'shared' section of the finder when you click all under network. (for the paths, don't use the quotation marks when typing them in, or anything else I say to type in - just type what is inside the quotes).
For advanced options, I use "soft" and check the "ignore set userid privileges" box as well. Click okay and apply (type in password for your mac) and as long as you set up the server correctly it should map fine.