I know I'm new but lets get straight to it.
NIOTE: This can be done with any build.prop!!
You need to be rooted (obviously)
You are going to need Root Explorer [You can buy this or you can get this from Applanet (Install0us for Droid) and download it there.]
I AM NOT ENCOURAGING PIRACY AND I TAKE NO RESPONSIBILITY FOR YOUR ACTIONS
You need to navigate to /system/ and then click Mount R/W. Then go to build.prop and click and hold until the menu pops up. Scroll down to Text editor and click that.
Now you need to scroll down until you find this. This is an example using 2.2 Froyo.
And you will need to change it to this.ro.build.fingerprint=verizon/voles/sholes/sholes:2.2/FRG01B/45394:user/release-keys
Then you will also need to change the line above this to the equivalent.ro.build.fingerprint=verizon/voles/sholes/sholes:2.2.1/FRG83D/75603:user/release-keys
To this.ro.build.description=voles-user 2.2 FRG01B 45394 release-keys
ro.build.description=voles-user 2.2.1 FRG83D 75603 release-keys
And thats all! You are officially OTA Free!