http://bushweed.blogspot.com/2008/09...x6-tablet.html
The fellow at the above blog gives some info about getting a Genius 6x8 Tablet & Pen working with Linux, with up to version 7.3 of the Xorg server. Note in the comments there, another reader has provided another URL which according to him goes into further details about advanced configuration options.
Hope this helps! (I found it via Google)
Sasha