cuftpd is an ftp server written in java.
Currently there isn't much information here, but you can find a README.txt here.
cuftpd is hosted by sourceforge.net and it has a project page here, where you can also download the latest release of cuftpd
The changelog can be found here. It is constantly updated, since it is a direct link into the svn.

cuftpd has several useful features:

The pzs-ng team have been very supportive of the cuftpd effort, and as such, have made modifications to their zipscript to get it to run flawlessly with cuftpd.

cuftpd should work on any ftp client, but if you find any bugs in a particular client, don't hesitate to report it to us and we will fix it.

You can get in contact with us (well, me, rather), either via the forums on sourceforge, or by visiting the #cuftpd channel on the EFNet irc network.

If you like to stay at the cutting edge of cuftpd development, or if you are just interested in seeing how it works, there is a publicly available Subversion repository online at sourceforge.

Update! Now you can find the api documentation here

Update! Now you can find instructions on how to mount drives into directories in windows here

Update! [h0d] has ported foo-pre to java and cuftpd under the name jfoo-pre.
You can find it under "addons" on the cuftpd site.

Update! There is now a 100Mbit.dk mirror of cuftpd up. This should help with the slow speeds of sourceforge.net
The address is http://cu.cokacola.dk/