Rooms is, so far anyway, the first and only IRC client for the iPhone. It's pretty stripped down as far as IRC clients go, but for simple chatting, it works really well. That said, it has quite a number of bugs, probably because it's only version 0.5. For the uninitiated, IRC stands for Internet Relay Chat, and involves real-time Internet communication on chat rooms called channels. There are hundreds of IRC servers located around the world, and is probably one of the oldest forms of Internet chat rooms.
When you first start Rooms up, you'll be prompted to add a new server, a port number, as well as a desired nickname, which is typical with most IRC clients. Then you can decide if you want to always connect to the server, plus you can set up default rooms (or channels) to join upon connecting. Rooms also has a nice console view that lets you see the connection status. Other settings include the ability to save chat logs, the choice to disable the iPhone's autolock feature (meaning it'll prevent the phone from going to sleep), plus the choice to stay constantly connected. The latter means that even when you get disconnected, the client will automatically try to reconnect you.
From there, you can join any channel you wish, and you can even switch between different channels by swiping your finger horizontally across the screen. However, when we tried to connect to two different IRC servers simultaneously, we sometimes found that channels would freeze and not show up. This is probably a bug with the first version of the software, but just keep that in mind.
The channel layout is pretty self-explanatory. The nicknames are along the top, while the chat goes on beneath it. Typing out chat messages is as easy as tapping the empty field on the bottom and then typing away on the iPhone keyboard. You can also toggle auto-correct off by hitting the "ABC" button. To send a private message to someone, you can tap the person's name or select the name from the pop-up menu on the bottom right.
There are a few limitations, though. You can't do the typical IRC slash commands, like /op or /me, so you'll be pretty useless as a channel moderator. Of course, chat and data transfers in the form of DCC (Direct Client-to-Client) aren't supported either. Also, as we mentioned, there are several bugs that can occur with this first version of the app. For example, one of the bugs I encountered was that the Disable Autolock feature sometimes crashed the app altogether.
If you can live with the occasional bug, though, I think this is a well-executed app, especially for those of us who simply must continue to chat online even when out and about. Rooms costs $0.99 cents on the iTunes App Store.