The organisation that produced the eDonkey2000 app has shut down. They settled out of court with the RIAA in the U.S. for summat like $30 million.
eMule, however, is opensource
and alive and kicking (mule... kicking... geddit?)
It uses the same protocols as eDonkey (with some enhancements) as well as some additional protocols. Not currently as widely used as eDonkey was but AFAIK should be around for a while yet.