Thanks to Dragon's Bane for this tip!

Maxum Rumpus 1.3.3 - high-performance FTP server software, regular and pro versions available

Stairways NetPresenz - full featured WWW, FTP, and Gopher server

WebSTAR Server Suite - integrated web server for web, mail, ftp, proxy

Other FTP servers for the Mac? Once you go to OSX you can use WuFTP (standard UNIX FTP server).