So, I said I haven't forgotten thee, and it's true. I've finally found some time to fix at least a couple of bugs and implement some features.
There were two places where mIRGGI could crash when receiving an empty message. At least NickServ on freenode did this and this is now fixed.
Also I'll add the long-awaited feature: backup/restore of settings. In the next version you can copy the settings to the root of the memory card and also restore them from there. This way you don't have to lose all settings if you have to reinstall mIRGGI, or you want to transfer settings to another phone!
Some other things will probably also get done, but we'll see tomorrow. In the morning I have an MCP exam, but after that I should have some time to do things. So just wait for 24 hours or so and you'll get it :)