IM+ has been available to devs but it’s now in marketplace and available for everyone in Marketplace. Here’s their description:
Chat in Yahoo!®, GTalk™, AIM®, MySpace™, Jabber, ICQ®, Facebook® and Skype on the go. No more SMS charges!
The wide variety of online messenger clients out there often means that no single one works for all of your contacts. They may be spread out among Google Talk, Facebook, Skype, Yahoo etc. To keep in touch, you have to spread yourself out across all of those platforms too. But this limits your availability to whichever service you’re checking in with at the moment–and the people who use that one.
If you’ve been frustrated with jumping around like that, IM+ All-in-One Messenger gives you a way to do all of your messaging from one place in easy and intuitive way.
They fail to note mention that it has push services so that the app doesn’t need to be in the foreground in order to continue to receive notifications. It also has group chat. The one service that’s missing is MSN\Live messenger but that wasn’t by choice as Microsoft required it to be removed as part of the certification process. It’s also $10 and lacks a trial but consider a single $10 fee to switch from texting to IMing (which is just a data plan) and it’s a solid deal.