Hey Jonathan,
I've been using
http://blogcarnival.com/bc/ to submit mine to various carnivals. The main drawbacks I've found:
- There are lots of old carnivals which are no longer running, cluttering up the list
- There's no way to know the "reputation" of a carnival; it could be very well-established or Joe Newbie looking for easy content (a set of links) for a post.
On the plus side, it's very easy to submit an article (you just fill in a short form) and it seems to have worked very smoothly so far for me!
Best,
Ali