I just got a phone call from an IG rep that said in the last few days, they are now allowed to open accounts for US citizens. Seeing as we were limited to FX, Oanda, and IB, an 4th competitor is welcome!
From here email, here is a link:
I rate IG highly
The company behind XM has also applied to enter the US market so looks like more competition is appearing.
The beginner's guide to FX trading