I've just had confirmation that RFG PC will be released on 11th September in Europe.

Just a few things to add for those who have not been following E3:

E3 gameplay trailer: http://e3.gamespot.com/video/6211460/

Darksiders stage demo: http://e3.gamespot.com/video/6211602/

The Darksiders Story trailer went up this morning: http://www.thq-games.com/uk/thqtv/index/3054
This video gives a little of the backstory behind War's character and gives a peek at some of the demonic forces you'll come up against in the game!

Here's a roundup of some of the other content out there today:
IGN Video have a walkthrough with a Darksiders Developer, covering 9 minutes of gameplay! http://ps3.ign.com/dor/objects/818225/virgil-games-project/videos/darksiders_spc_commentary.html

Eurogamer's Will Porter went hands on with Darksiders: http://www.eurogamer.net/articles/darksiders-wrath-of-war-may-hands-on
VideoGamer has a preview of the game here: http://www.videogamer.com/xbox360/darksiders/preview-1719.html
TVG also have a preview: http://www.totalvideogames.com/Darksiders-Wrath-of-War/preview-14127.html