Whilst the SSH clients I found for my phone were an interesting gimmick, to be honest they weren't actually much use because of the small screen on the phone - a simple 'ls' fills up screen after screen, even on the tiniest (i.e. unreadable) font setting. I thought IRC might just be doable, and in fact there are several Java IRC clients available for phones. I tried WLIrc and jmIrc. jmIrc was originally a fork of WLItrc, and the shared heritage is evident. I couldn't load either of the clients over WAP onto the phone, but they both installed fine after I downloaded them and squirted them into the phone via the IR link. Once on the phone, both clients were configured as detailed in step 5 of my SSH client post.
WLIrc proved to be less than usable as it kept dying with a Java null pointer exception. jmIrc however seems to work fine, with just one minor quirk that I've been able to find so far - If you modify a connection profile and then quit rather than saving the entry it loses the entry, and the next time you start it it dies with an array bounds exception, the only fix is to reinstall.
Once you have started up the client you can set up profiles to connect to your favorite IRC servers, specifying which channels you want to join, your nick etc. When you connect to a server each channel is indicated by a small coloured square on the screen. Backgrounded channels that have had traffic since you last viewed them are highlighted by changing the colour of the indicator square for that channel. You can switch channels with left and right with the joystick, and you can scroll up and down with the joystick as well. The number keys can be used to page up/down a screen at a time, home/end etc. When entering text with the fold-out keyboard closed you can use the phone's predictive text feature to compose your messages in the same way that you would if you were composing an SMS message. All in all it's an impressive illustration how careful interface design can yield a truly useful application even when the platform it is running on is limited. If I had any boring meetings to sit through I'd certainly be using it to chat to people I'd rather be communicating with, but one of the benefits of being a remote employee is that I very rarely have to sit through any such meetings :-)