Though Bwindi is relatively safe, kidnappings are rare but do happen. For an idea of the risk of visiting places in Uganda piratically by the ""Democratic Republic of Congo"" border, see the documentary about Mark Ross and his struggle against the Interhamwe on the Locked Up Abroad: Uganda episode.
fees/permits
As of June 2007 all gorilla tracking costs US $500 for a non-resident - though worth it as it is an unbelievable experience.