http://liz-marcs.livejournal.com/275028.html
You can transfer everything including comments (with the exception of some embedded content and polls) to your own hard disk - this is fast and easy, and all of the original posts (but not comments, embedded stuff, or polls) to another blogging site - which works but goes slowly and is a bit of a pain.
So if I'm all over your friends list on Greatestjournal today that's why...