I believe this is the one you want:
http://code.google.com/p/prs-plus/do...r.zip&can=2&q= :-)
The install guide is here:
http://code.google.com/p/prs-plus/wiki/InstallGuide
Basically, you need to do this:
1. unpack PRS+ installer zip (available in download section) to your SD or MS card (using empty card is recommended) or to the Internal Memory of the reader.
2. If you put it into external card, enable SD/MS card scanning in PRS+ if you've previously disabled it.
3. Follow instructions on the screen.