I've been looking in on the OpenStreetMap project every now and then but have not actually tried using it or contributing to it. The project is a worldwide map that can be collaboratively edited by by anyone who signs up for a user account. It is an attempt to provide a free alternative to the for-fee maps used by most commercial mapping software.

ReadWriteWeb reports that there is a new reason to take more interest in the project...

Flickr Now Supports OpenStreetMap Tags

The article notes that the iPhone Roadee and Waze apps use OpenStreetMap. And OpenStreetMap's wiki merchandise page notes that there are also mobile apps using OpenStreetMap for Windows Mobile (Pocket PC), Symbian S60, and the now defunct Palm OS. There isn't much out there in the mobile space that uses OpenStreetMap. However, it is worth keeping an eye on. And, if you do finding an interesting mobile mapping app that works with it, don't forget that Flickr will now work with its node ID data.