I found a very interesting site last night.
Betkurus.comYou can bet in various currencies without conversion by using their bitcoin-to-fiat conversion service in real-time on their exchange platform. Pretty cool right? I can just enjoy betting with fiat currency without needing a bank account.
Another thing I would suggest is Neteller, allows you to send bitcoin to your deposit account and then play on the sports sites like bet365 with dollars. The only drawback is that it doesn't yet support BTC withdrawals, which might be solved once poker stars starts accepting Bitcoin.