Since reading Murky Depths I've become quite keen on comics. My first, a one-pager, was published in Murky Depths #15, a second has been accepted for publication, this time a 5 page script, and another 2 pager is under submission there. Murky Depths accepts completed comics and also scripts which they will match up with an artist.
Of course, not all comic scripts I write will necessarily be suitable for Murky Depths, so where else might I submit them? I had a quick scout around the internet, and this is what I came up with so far:
Future Quake accepts completed comics of 5 pages or less.
2000 AD (which even I had heard of in my pre-comic days) accepts 5 page scripts for their Future Shocks section
OrangUtan Comics wants completed comics of 6-8 pages
Panini Comics publish a wide variety of well-known comics and are looking for sample scripts
Engine Comics wants scripts of 8 pages or 3x8 page serials
Markosia are looking for completecomics or graphic novels
There are more details on each of their websites.
There are probably others - I didn't spend a huge amount of time searching. The usual market listings like Duotropes and Ralans don't seem to include comic markets. Maybe I'll drop a hint.