Electronic book publisher Lulu (http://www.lulu.com/) told its top authors over the weekend that their electronic books can be made available on Apple’s new iBookstore that is debuting with the launch of the iPad on April 3.

According to “Digital Beat” (http://macosg.me/2/1t), Lulu said it would automatically convert books for submission to the iBookstore — unless authors didn’t want their books published on the iPad. According to R.R. Bowker’s Books in Print database, some 276,489 books were published traditionally in the U.S. in 2008. Lulu alone published over 400,000 titles last year.