Although they do charge a small fee, something like 2.9% + $ .30 (don’t quote me, I’m just the messenger). With this new option, link your credit card and bank account with PayPal and pay your friends without needing cash.
Mashing-up with Bump, allows users to make paying people just a bit more entertaining. My buddy needed to pay me for a parking validation the other day so we "bumped" phones. Bumps app recently added Facebook integration, the list goes on.
App developers are starting to get very creative with collaboration mash-ups that shared the best technology with the best features and design. Another great example is Occipital, makers of Red Laser. From their site "Occipital, LLC is a technology startup focused on mobile visual search, founded by University of Michigan alumni Jeffrey Powers and Vikas Reddy."
Apps such as Alice.com, Cor.kz, and many others are using Occipital’s Red Laser technology to make product search a lot quicker.
I think it’s great that although the iPhone OS is essentially a close system, developers are teaming up to share and license technology.