I just recently purchased a BlackBerry Bold 9000. It has been used for a year with Rogers and is still currently locked with Rogers. The software has just been recently updated by the original owner to a OS 5.0. Can this phone be unlocked and be used with any other carrier?

Usually it's no problem. If a previous owner tried 10 times unsuccessfully to enter an unlock code it will be permanently locked to the original carrier though. Email HorizonWirelessOnline.com - Horizon Wireless, The World’s Cellular Repair Center ß and inquire with them.