Livejournal users can use their Livejournal identities to log into Dreamwidth through this page. The process sends you back to Livejournal's site to verify your LJ cookies; then it allows you to create a sort of lightweight account that can't publish journal entries but can set up a "reading page" (their equivalent to a friends list), write comments, and so on. Importantly, people with regular accounts can grant read-locked-entries access to OpenID accounts, so you can use it to keep reading the locked entries on your friends' journals even if they migrate to Dreamwidth and you don't.
I'm mentioning this here because at the moment I only have two readers, there aren't likely to be many more of my friends making it onto the system with full accounts until May, and I crave attention. :-)