I have IE 9 and its still looping, switched to firefox myself for the mean time.
After being pestered via whisp
If you clear you temp internet files on the first login it will prompt for username and password and work correctly however if you tick the remember password box and login and then log out on the next login when you just enter password it loops.
The login bar along the top seems to work regardless of whether you have entered the username its just the login button that turns into a play button that loops (for me) on logins where you are only entering the password so a simple solution seems to be to un-tick the remember box and let auto complete stick the username and password in till they have fixed.