Bitcoinity's site is probably one of the better ones. http://bitcoinity.com/markets http://bitcoinity.com/markets You need to watch the other US exchanges as

Bitcoinity's site is probably one of the better ones. http://bitcoinity.com/markets http://bitcoinity.com/markets You need to watch the other US exchanges as well, not just MtGox. It's basically impossible to get USD from MtGox right now, making it a very poor benchmark for the actual exchange rate.