http://rzuwtppveur6yh3n2in7trmddgrkuhww4eb2znykgjwubihfpljiyuid.onion
There are plenty of other programs you can use with Tor, but we haven't researched the application-level anonymity issues on all of them well enough to be able to recommend a safe configuration.
Our wiki has a community-maintained list of instructions for Torifying specific applications .
Please add to this list and help us keep it accurate!