What is the timeframe in publishing a children's book? (How long does it typically take from my submission to the publisher's acceptance, how long until advanced reading copies come out, and then how long until the book is published?)

Unfortunately, there are no definitive answers to your questions. Some publishers respond right away if they like a manuscript (one editor called me within two hours of a submission), and some publishers, if they are overwhelmed with manuscripts, can take six months to respond. If an editor likes a manuscript, she probably has to share it with the marketing and art departments, and then present it at an acquisitions meeting. That can take time.

As for how long it takes from a publisher's acceptance before Advanced Reading Copies (ARCs) go out to bookstores and reviewers, again, there's no definitive answer. Usually the author has to go through revisions with the editor, and if it's a picture book, the text has to go to the illustrator. The illustrator may be booked for a while and now the editor has to wait for the illustrator's schedule to open up. The illustrator might take six months to create the art, and then everything has to go to the printer. So, in general, it may take 18-24 months from the time of acceptance to printing. In some cases, it can take years from acceptance to ARC, especially is the book is being published to coincide with an anniversary event as a marketing hook. For example, in 2008 I sold a picture book text about Hank Greenberg and Jackie Robinson, but the book won't be published until 2012 so that the publication can coincide with the 50th anniversary of Jackie Robinson's induction into the Baseball Hall of Fame. That's a four-year wait for the author!

And, finally, as for how long it actually takes for a book to be published after ARCs go out, it's usually a few months, sometimes weeks, but long enough before publication so that the publisher can generate enthusiasm for the book among reviewers and bookstore owners.