I've used PSPVC :: PSP Video Converter for a long time... downloaded originally for my PSP, it's stayed on my PC and I've yet to come across a simpler or more effective converter (for my needs at least). Lots of useful presets... for the TouchPad I've been just picking the default or animation preset for PS3/Xbox and dropping the resolution (if needed) to 768x432 (if 16:9).
I also appreciate that there's no ads or annoyances, even on the website.
The fastest way to install Preware on your WebOS device.
Put your device in Developer mode.
From your PC download the Preware installer from http://get.preware.org
Run the Preware installer while the WebOS device is connected with the USB cable to your PC.
Vualla Preware is installed.]