When I backed up my 3g I assumed the apps backed up as well? Because when I plug in my new 3gs and click on the apps tab, there are no apps there for me to sync. What am I missing here? I really appreciate your help!!!
No, Apps never backup. You gotta sync them back from your computers itunes library.
You needed to transfer you apps into your itunes library.
So when you open up itunes and click on the Apps icon under Library, music,movies, podcasts etc.. there's nothing there?
No apps?
You need to plug your iphone 3G back if you have it available and right click under devices on your iphone 3G icon and select "Transfer Purchases"
That will copy/transfer all your apps from your iphone 3G to your itunes library and then you will be able to sync them back to the 3GS.
Or you can redownload them all again for free with the same itunes account login.