You can get the OS from your carrier's website as they would be the ones most likely having it. You can just google search your carrier's name with blackberry updates. To install the OS you will have to get the BlackBerry Desktop Manager if you don't already have it. Be sure to back up your phone before you update it though because most likely everything will be gone once you update it. The update seems to be a good update (unlike iOS 4 for the iPhone 3G...what a nightmare!) and doesn't seem to lag the phone that I know of. The only con that I know of is that to open up your full application list you have to press the menu button twice, or scroll up once and click the trackpad, rather than pressing the menu button once for doing the same thing. You can just update with a file of an older OS if problems/warranty service deem it necessary the same way that you updated it. Don't disconnect it at any cost because your phone could become bricked (unusable). It will not affect your contract however if you download an OS not from your carrier, then your warranty could be nullified, but if it is from your carrier, than there shouldn't be any "legal" problems with this. I personally do not own a BlackBerry but I do know alot about technology in general and quite alot about BlackBerry's in detail.
