One of the hot topics and potential killer applications for cell phones (if such a thing can exist on a device that has the potential to be used in so many ways) is user generated content and social networks. One of the challenges has been with moving content from the phone to the PC or vice versa.
We've spent a lot of time doing research on how people interact with their social networks with their cell phones. It's not about shrinking the experience – it's about mobilizing some core components that make sense along with personifying the cell phone (e.g., sharing it's profile, sharing my presence/location), allowing people to share, enabling them to communicate, etc.
One of the components that I think is a good fit for mobilizing is giving people the ability to push content out to their own phones or allowing their friends to push UG content from a friend's site to their phone. Artists can use such functionality to distribute their content. Obviously, there are many varieties of this concept and how it could be used. 3Guppies has a widget for sites. Bango today announced a button for doing the same. I haven't had the chance to try it yet, but I like the concept.