well have a look here there are lots of useful ebook posted by the user lamialestat so all credit goes to him. =D

http://www.esnips.com/web/Learn-Japanese?docsPage=1#files

to download the file just register as a member, It wont take you 2 minute to do so. lol. But be sure not to register with yahoo mail.

p.s: hope i am not breaking any rule here by posting a link here. lol.