It has been a few months since I have used or gone through through my list of
Blog Directories for Adult Sites. I add a few fake/old posts, beef up with a few fresh ones, and submit away.. On average I can get a pr2 and sometimes 3, just from the directories.
A nice starting point at least.
I also have
mainstream blog directories, most are free and take several tries to get listed. It's really better just to research the top 20 decent ones and just pay to get listed.