Sabifoo makes IM to RSS publishing as easy as I can possibly imagine it. I created a test feed for Clohessey's bar in Limerick, added it to the Open Irish Directory and then published to it from my Nokia 6630 using Agile Messenger. Google Talk now communicates with Jabber which is what makes it all possible (though other IM protocols are also supported).
I inserted the test feed under Entertainment & Shopping -> Pubs & Restaurants -> Limerick -> Clohessey's -> Live Feed which is best browsed using an OPML+RSS reader like Taskable or OPod. I pretended it was last Saturday night just after the Munster rubgy game and sent an hypothetical message from the manager. I'll remove it shortly but I just wanted to demonstrate the possibilities for real-time 'broadcasts' by entertainment venues to their clientele. Of course text messaging (SMS) would be even easier than IM but we're still waiting on a SMS -> RSS gateway.
NOTE: I'm not sure how the caching works with Taskable and OPod but it can take some time after updating the OPML file before it appears in those browsers. So if at first you don't see anything please come back again :)