In xcode 4.2, sometimes when you\'re going to run your ios proj on simulator, the status windows says \"Attaching to myapp\", and just gets stuck there... until you cancel. Now,
Did you recently upgrade to OSX 10.7.2? I started having the same problem after I upgraded. I noticed that the Simulator always get stuck if I'm connected to a Wi-Fi network that forces Captive Portal authentication. This happens with other apps as well (Chrome, Safari). I'm not really sure why this happens, but I did read that 10.7.2 has issues with Captive Portal authentication.
Anyway, in my case, I repaired disk permission from Disk Utility and rebooted my machine. This seems to resolve the issue.