Not an audio book fan, either. I've borrowed some for the kids on long trips (Harry Potter) but I always find my attention wandering when trying to listen.
Personally, I think the participatory model is a niche market. And if you have a windows, palm, or symbian phone you can already read ebooks on it by downloading and installing the appropiate reader. And if your phone is internet capable you can purchase books at ebooks.com and read (most) online.
You won't catch me reading books on a cell phone except if I'm stuck somewhere and I forgot my reader or my Palm.