Here is a Beginner's guide to InsaneJournal. In short, it's a lot like LJ used to be, but with a different interface. LJ was, at some point of time, built by users based on an Open Source script. And the good thing about an OS script is that companies which have nothing to do with one another can run this script.
If you really don't like LJ at all anymore (I'll admit, I don't -_-), here's some tools for site migration! I've tested it... It works, as far as I'm concerned, to a reasonable degree. You can use Semagic (as described) to synch similar sites, or crosspost to both sites at the same time.If you're using mac/linux, try this program instead.
Don't want to sign up to InsaneJournal?
You can comment on both sites using OpenID, if you don't wish to sign up for a new account. Only thing with this method is that you can't make a new post.
Help?
If anyone is good at HTML/CSS, please help me figure out how to make the IJ layout same as the LJ layout. ;_; (I copy pasted the overrides...)