What about JAP ? http://anon.inf.tu-dresden.de/index_en.html

But like they say:

Attention! The first release of JAP is downloadable free of charge and already protects your privacy against most observers like your ISP, your network operator, or your boss. However, this version does not yet achieve the full security and anonymity that we strive for. It does not protect you against an adversary who has the capability to observe all communication links on the Internet.