Now a days themes are pretty standard on any Android device. With custom home launchers like ADW and LauncherPRO giving every device a chance to look unique, some people wonder why they should root. Beyond custom ROM’s that are a million times better then what is offered to a stock user, we have MODs that are similar to this one by lenny hodapp at Rootzwiki.
He went through and learned how to theme out just the dialeractivitytab.apk, courtesy of a guide by XDA member Paul627g, and created a huge collection of themed dialers for everyone to enjoy. Near as I can tell, these will work on any rooted Galaxy S 4G device. To make sure you can use them though, check in your system/app folder to see if that APK is listed. You can do that through ADB or Root Explorer.
To install the files you will want to use ADB to push the APK to the system /app folder or you can use Root Explore as well. Be sure to make a back up of your original file as a precautionary measure.
If you would like to check out what he has put together or request certain images to be made, then head on over to Lenny’s Rootzwiki thread and take a look.