Converting to friends-only

Is there an easy-to-use (for the layperson) client that converts all posts to private?

I'm trying to convert my account to friends-only, retroactively. Seems pretty impossible.

Also, does anyone know how long it takes Google's cache to expire?

Yeah. That's about the shape of it. I didn't realize google indexed LJ. Go me. Let's hope my prof doesn't google his own name too often.