As I’ve mentioned earlier, I fully intend to publish here the complete, step-by-step procedure that you can follow in order to get Ubuntu Linux up and running on your PS3.
However, I’m afraid it’s going to take me some time to write down the whole process and post it here.
If you’re not in a rush on this, please stay tuned for updates that I aim to post here over the next few weeks. In case you need to get on with this (much) faster, and don’t mind shelling out about $30, I suggest you check out this package called: Linux for PS3 Installer.
While I’ve not actually used it (simply because I’d already done the whole thing the hard way long before I came to know of the existance of this product), based on my study of it’s web site, I do think it will do the trick for you – and save you a few hours of your time too!
You can check out the Linux for PS3 Installer here.