sancho is a gui that connects to a p2p core application. Power users that use p2p applications usually choose one that has core/gui separation.
The sancho project is written for fun, but also to test some new and exciting technologies. It is written in Java using the SWT widget toolkit and can be compiled on multiple platforms with the gcj compiler to native machine code (java=slow and bulky? not anymore! no external java runtime required!). Windows, Linux, OSX and other popular operating systems are supported.