[bridic]

If you are just looking for scrolling then the FTouchFlo will work great.

The FTouchSL will allow you to add gestures as well.
Down-Up
Up-Down
Left-Right
Right-Left
Down-Left
Down-Right
Up-Left
Up-Right
As well as all four corners

I like the FTouchSL because I do not have to use an larger program (UL, SPB MS, etc) to get what I want.
Just a Up-Down gesture and bam!, Opera Mobile