What do I need to build a Cross platform Group chat mobile client?

I was thinking about this the last few weeks until I saw a blogpost somewhere talking about the rise of HTML5 on mobile devices for 2011.

I though to myself, HTML 5 would indeed be nice to create a cross platform mobile chat client. But i'm kinda noobish and I was wondering if something like XMPP would be able to come close to a blackberry messenger group chat experience with the Delivered, read, etc msg status.

Anyway, Happy new year to all of you :)