I've been a fan of PayPal since its early days, when it was originally designed for beaming money from one Palm to another. A lot has changed since July 1999 and today PayPal has released a new version of its PayPal app for iPhone that lets users Bump cash to each other.
The new PayPal app lets you type in the recipient's email and send money the old PayPal way, or simply "Bump to Send Money", thanks to the company integrating Bump Technologies' API.
I remember reading a while ago that the folks behind Bump were working on a business model that involved licensing the technology. A quick look at their site shows an API page, which looks to be offering the API for free once you fill out a form. It's not clear if this is a restricted API and if PayPal may have paid extra for a bit more access, but one this is for certain--with PayPal on board the company will no doubt either secure some serious funding or be ripe for acquisition.
Download the new PayPal app at itunes.apple.com and start Bumping some cash around today.