A cool new blog has surfaced. Apperantly its Quentin Trantinos own blog (Old url no longer works, instead its a spam blog there – the old url was: http://qtdiary.blogspot.com/ ). If you want to “read all about it”, there is an article about QTs diary over at Wikipedia
From the writing I have read so far it seems likely it is. Judging from how he usualy communicates in interviews etc.
BTW: If you are a Quentin fan, you might just get a blast out of Christen Nelsons story about her chance meeting with Quentin
[Update] It is a fake, according to Tarantino’s publicist.