Samsung Galaxy s2 stuck on boot screen after an OTA upgrade
Have you flashed the phone before and do you have any new boot loaders on it? What kind of recovery mode is it booting into? ClockworkMod? Or does Samsung have its own recovery?

If possible I would suggest maybe downloading the correct ROM for your handset from cyanogenMod and putting it on your SD card then try flashing that on. Do a clean wipe and then set up your Google account again so you have all the numbers on phone again. 

On my phone I have installed clockwork mod and new boot loader so I can flash the phone again if the ROM ever gets broken. Obviously i don't know exactly how your phone is set up so i wouldn't be able to give exact instructions on how to do it. 

EDIT: I would suggest flashing a ROM onto it from recovery if its not booting then what you have in the mobile world is probably a "brick". Dont see many other optuions to be honest.

Bill