So my friend gave me her old iphone 3GS and I'm trying to set it up.
I have the old MacBook (ie. not OS X) and therefore cannot install iTunes 10.1 or later, which is causing me problems as I can't use the iPhone.
If you just need to set it up go to a retail Apple store or Best Buy and set up your 3Gs there. Granted you will not be able to have back ups and the like but if you're simply looking to get the phone activated and set up this is one solution. Also it may be a good time to upgrade your computer and operating system.