I almost linked to this, too, in the "Western Union says Bitcoin is not ready for international transfer" discussion[1].
The interesting thing about Hawala is that it provides a ready source of liquidity in local currencies. If someone was to link the two (ie, a local Hawala agent accepted a Bitcoin transfer from an untrusted source, and then moved the money via the trusted Hawala network) then almost all the problems of Bitcoin would go away.
It would also set just about every TLA agency in the US looking at you (Semi-anonymous crypto-currency which has been used in drug markets + untracable Islamic money transfer network? There's a techno-thriller plot right there). OTOH, Hawala agents seem to ignore US laws at the moment, so they might not care about this either.