These are very basic instructions on how to push stock apps back to your phone. I will make a more detailed post when I have time.

Update (11/24/09) : Don’t want to worry about how to use the commands to push the apps back to your phone? Please check out our auto installer.

Open a command prompt and navigate to your Tools directory from the Android SDK. You should have this from when you rooted the phone.

Type the following commands:

adb remount
adb push c:\folders\yours-apks\stock.apk /system/app

Just reboot and whichever app you pushed back should now be there.