There's one webcomic I like, nothing serious but it's funny and cute:
http://mytholol.smackjeeves.com/archive/
Here are other entries in that website. Some look amateurish but others have nice art, I haven't read them, though, so I don't know if they're good.
http://www.smackjeeves.com/search.php?submit=submit&comic_title=greek+mythology&submit=Search
I'm developing a webcomic too, I'm writing and a friend will do the art. It will take place during the argonauts generation (and maybe beyond if the artist doesn't get tired of it, lol). Sadly there's nothing to show yet, it will take a few months to start publishing, then it will be updated weekly. The bad news is the comic is originally in spanish, so it may suffer somewhat with my translations; I try my best, but my english is far from perfect.
If you've found other webcomics please do share a link.
I'll be looking forward to the one you're creating too. What kind of webcomic is it? An ongoing story, comic strips, a mix of both? Tell us something about it. When do you think you will start uploading pages?, or -if you started already- where can we read it?