Instead, we need to join a GOOD file-sharing program on an existing network. Which means we pretty much need to agree on what's 'good'. :P
At the moment, I'd say that's probably Shareaza, just due to its ok (but not great) support of multiple networks.
BitTorrent is excellent, but it's NOT a file-sharing network -- it is totally lacking search capabilities and is VERY vulnerable to being scanned and attacked by hostiles.