I falshed MIUI on the AT&T galaxy s2 and it works but has some very annoying issues like the home button works as the back button so if your browsing on the web you cant go home you have to keep pressing back until you finally go home. Also, you can't install apps from the market. I made a video demo, search on youtube MIUI rom on AT&T Galaxy S2 Demo and its on my channel (lawrenceseverin)