At some point (last year) I was discussion with Mozilla regarding location-aware application development for the upcoming phone-based web browser. Too bad that did not materialized into the code... Still browser is good and hopefully will capture well deserved attenshion and appreciation of the users. In my opinion it is superior to the much-hyped iPhone browser.
Here is the link for the app:
Win Mobile is the only platform at the moment. I am sure other builds will be available soon.