According to the Kodu website, Kodu has finished being reviewed; and the creators are deciding if it should be released. The site also says that it may take up to 48 hours before it is released, after being reviewed. An XNA Premium member (Darth) who tested Kodu said,

"I was checking out the XNA forums and it looks like someone has rejected Kodu, for framerate issues when a high number of objects are on the screen. If someone else fails it the game will be put in "jail" for a week and then it can be placed into review again. :("

This could mean a long wait for Kodu...