Well, I've finally gone and done it - I've now got a project on Google code and I now feel like a proper part of the coding community. We'll see how long that lasts. I've just uploaded the first version of my AIR ApplicationInfo class, and no doubt I'll be adding, extending and improving on it in the future - with the added bonus that now I'm not the only one who can contribute. You can access the project here.
How did I do it? Well, it's really all thanks to Internet Duct Tape's "Getting Started with Google Code Hosting, Subversion, and TortoiseSVN without feeling like an Idiot" article, which does exactly what it says on the tin. I got a Google Code project, learnt what the hell TortoiseSVN actually does, and did it all within 10 minutes.