I just left a career at Random House, in children's books sales. I'm not actually all that down on self-publishing. There have been some success stories, but it really depends on the quality of what you have written, and what you do to promote and sell it afterward. I guess anyone can pay to get their book published, so it really doesn't signify unless the book is then successful. I'm not sure why poeople think it is the kiss of death, though, but would love to hear other perspectives. I can't recommend lulu or publishamerica though--I have heard horror stories on their rights agreements.
These women self-published a picturebook and did very well with, going on to acquire an agent and a major publisher, and a lot of $$!Sold to Lyron Bennett and Dominique Raccah at
Laura Duksta and illustrator Karen Keesler's
179,000-copy self-published picture book I Love
You More in a pre-emptive significant deal, to
be a featured title at Bologna and fast-tracked
for publication in fall 2007 (World).
I would recommend joining the Society of Children's Book Writer's and Illustrators, they are also a good source of information, and their membership packet and website will give you a lot of good info.
As far as getting published now, have you actually written the book? If so, any of the books and societies mentioned above will have helpful information on writing a query letter to agents/editors. I am of the opinion that you do need an agent, especially if you want to be published by one of the larger publishing houses. I would advise reading a lot of books in the genre that you are writing, and seeing who publishes them. Check out the authors and see if they have blogs, and if they mention their agents on their blogs--that might give you an idea on who to submit.
Also, if you join CBC or SCBWI they hold regional conferences that editors often attend and hold workshops. That's a great place to make a connection and get your work in front of someone.
Lastly, if you are writing a picturebook, Harpercollins is holding a contest right now, celebrating GOOD NIGHT MOON's anniversary. The site is www.bedtimeclassics.com
and the contest is open til 7/15.