After discovering about patent No. 7,479,949 which was approved on the 20th covering multi-touch devices that use heuristics, I said it would cause future devices some problems including the Palm Pre. This statement I stand by, I would however like to just point you towards an Engadget mobile article that they posted today going into much more detail about the subject.
It’s a long read so grab a cuppa (or a beer) before clicking!
http://www.engadget.com/2009/01/28/apple-vs-palm-the-in-depth-analysis/
Enjoy
A