1) Backup current apk & odex files
2) copy over new apk & delete the odex
3) restart your phone. If you don't you'll get a bunch of force close messages.
I was able to take the TouchWiz30Launcher.apk from the Vibrant and replace the stock version on the Fascinate. What this buys me is the ability to have an Alphabetical grid option in the app drawer. I hated not having the grid in alphabetical order since I knew it was an option on the Vibrant. I posted this on the AC forums and since people liked it over there I'm posting it here.