No, it won't be that easy.
That's what the MyLJ project is about.... all the tools, clients, servers necessary to do that yourself, off your own server, or a combination of your server and another, like livejournal.com's.
Releasing the source, however, may expedite development of MyLJ ... we'll see.
So far the code contribution from lj_dev people has been minimal, understandably. However, from the enthusiasm and helpfulness I see here, I suspect things will speed up shortly.
I just hope that opening the source doesn't stall MyLJ development, since people might think MyLJ isn't necessary if all the code is open. But the current code is very livejournal specific. It'd need a lot of changing around to get it to be more general. However, as MyLJ development is currently pretty slow, it can't get much worse.
Also, you won't need huge servers to run the code.... you won't be doing 50+ requests/second like LiveJournal. You'll be doing one request every 5 seconds. Your spare P90s or whatnot will handle it fine.
