Here are a few links to sites with some UB content.

The beaddventure has several episodes with unbirth - I try to maintain a list on my page.

Smartgroups Unbirth group A group I created to attempt to replace the various ones yahoo killed recently.

Rochndil's story page is the repository for all the UB stories written by Rochndil, who I consider to be one of the best UB authors out there.

Mamabliss.com has a wide range of fetishes covered by the comics, many of which don't particularly interest me, and several that do. If you're into vore, UB, or various odd stuff, you'll probably like the site, and the artwork is very good. The UB works that are there are quite well done. My favorite is the recent one, "Sugarsnap." It is a pay site, at least to see anything but the most recent panels, but worth the fairly low membership fee, IMHO.

Eka's portal is a nexus and central repository for a lot of related obscure fetishes, including unbirth.