Big publishers are flocking to the iPad, readying to publish electronic versions of their bestselling books on Apple’s much-anticipated tablet device due to launch April 3. But smaller publishing houses are making the move, too, including self-publishing service Smashwords.

Smashwords, a site where writers can publish their own e-books, said today it has signed a distribution deal with Apple to put its books into the iPad iBookstore. Mark Coker, chief executive of Smashwords, said in an email to authors that his company has been working on the deal ever since the iPad was announced. And, yes, this means that unpublished authors can sell their work on the Apple iPad at virtually no cost.

To get books on the Apple store by launch day, Smashwords authors have to have their works submitted to Smashwords’ premium catalog by March 31. The book has to be in the EPUB format and have a big cover image.

The deal hasn’t been announced yet, but I got the notice from Smashwords’ Coker because I published my own e-book, The Xbox 360 Uncloaked, on Smashwords back in December. It was a very easy process. I took a Microsoft Word file and uploaded it to the Smashwords site, set the price, and decided where I wanted the book published. Smashwords published it in nine formats and began distributing the book over a number of weeks to sites such as Barnes & Noble, Kobo, Stanza (on the iPhone), Aldiko and others. The Kobo site is the way to get e-books on multiple mobile platforms such as Palm, BlackBerry and Android. So Smashwords has the potential to get unpublished writers in front of millions of users.

The company also said it is adding ISBN (International Standard Book Number) support as required by Apple, and it is preparing a large delivery of books to Sony’s e-book store. Apple’s requirement is that all e-book prices end in .99, so you can sell at 99 cents, $1.99 etc. The price must also be less than the print counterpart. The distribution cost to get the book on the iPad is free. Smashwords and Apple divide the remaining 40 percent of the e-book price.