Nimbuzz recently launched a beta version of their service. It provides free instant messaging as well as a very cool VOIP service for your mobile phone (like what Skype provides for your PC). Best of all (at least from my perspective), their IM back-end is powered by Wildfire. Nimbuzz is a great example of how communications are converging in innovative ways. As we're seeing with a number of customers, Wildfire is in the thick of that process.

My lame U.S. phone doesn't have J2ME support so I haven't been able to actually try the service yet. I'll have to hunt down somebody in the office with the required equipment...