If your rooted, you just copy the apk's into the /system/app folder (i use root explorer to do this). Make sure you backup you original homescreen apk and other apps that might get overwritten. There's no fastboot files to at this point to reinstall the system again so if you don't backup the original you might be stuck not being able to upgrade once the "real" jeally bean comes out. Change permissions to match other apks in the system folder, then reboot. That should make them system files.