UPDATE: There is a new link to SamMobile Firmware site for the stock TAR file. Register and account and download the stock firmware and you will be able to update over the air. Thanks to @ledfrog for the info!
Note: This is also suppose to work for the Rogers version and I think the link to that ROM is below the one I clicked on. It is the SGH-I727R and I think the R is for Rogers. As alsways do you research before doing something like this because I am not responsible for YOU damaging your phone. Good luck and have fun:
Skyrocket drivers: http://bit.ly/zfpMUi
Stock TAR for SGH-I727 :http://j.mp/Ng0Cht
Odin 1.85: http://j.mp/w7BwdI