Could somone please explain to me the different DVD upscaling options?

In the menu under BD/DVD Settings. There is now the option for DVD Upscaler.

It gives you 3 options:
Double Scale
Normal
Full Screen

Can somone please explain these to me? I set it to normal not knowing the difference, but I don't know the difference.

also, it says it wont upscale copy protected DVD-R/RW's. does this mean I can't upscale movies that I buy? (sorry for my ignorance)

http://www.us.playstation.com/ps3/network/updates/PS3_180_update.html#upscale

I think this should cover it all for you ...

thanks for the link. one question though:

Double Scale* Upscale and display with double horizontal and vertical dimensions without changing the proportions.NormalUpscale and display at a size that matches the screen size.

So my understanding of this is normal = 720p, double = 1080i/p (whichever is the higher of the two your TV supports). is this right? Also, why would somone use full screen?