PocketFrog provides double buffering using the native screen format. That means that the backbuffer is properly oriented as to minimze tearing.
Unfortunately, there is no (known) way to sync the "flip" with the "refresh" of the screen. This means that in some cases tearing is unavoidable.
You could try to limit the framerate to somethnig like 30 fps and see how it goes.
Note that tearing will be more noticeable when the screen image is scrolled perpendicularly to the actual physical orientation of the display.
ex: on IPAQ 38xx, scrolling vertically will produce more tearing then scrolling horizontally.