There's just one site with the press release, but you can find the games on Steam so it's confirmed.

Latest from Legendary Studio Coming to Leading Online Platform

September 12, 2008 - Crytek and Valve today announced an agreement to bring Crysis Warhead and Crysis to Steam, a leading platform for the delivery and management of PC games and digital content with over 15 million accounts around the world.

"The millions of gamers logging into Steam every week to play today's best PC games are going to love Crysis Warhead," said Avni Yerli, Managing Director at Crytek. "Crytek Hungary has done a terrific job creating this new experience while optimizing CryEngine 2, and we're looking forward to delivering it and the original Crysis as our first offerings on Steam."

"Crytek is one of the industry's great success stories, emerging new technology and talent," said Gabe Newell, president and co-founder of Valve. "Crysis is one of today's leading PC franchises and delivering the original and Crysis Warhead via Steam is landmark for the platform."

The follow up to Crysis, one of the highest rated PC games of last year, Crysis Warhead will take players through the parallel story of Sergeant Michael 'Psycho' Sykes as he embarks on an intense, explosive adventure on the other side of the island. With waves of more challenging human and alien enemies to navigate through, players will once again be outfitted with the revolutionary Nanosuit and an arsenal of new weapons and vehicles to help Psycho complete his critical mission.Crysis Warhead will also come with Crysis Wars, a tailor-made experience for multiplayer gamers, featuring three diverse match types and 21 maps.

Crysis Warhead and Crysis will be available for pre-purchase via Steam starting this weekend, and expected to be released in mid September. Both games are published by EA Partners. For more details, please visit www.steamgames.com
and www.crysiswarhead.com.

Source: http://csnation.totalgamingnetwork.com/view.php/press/steam-crysis.csn

Apparently EA is not involved (and you still get a $5 discount if you get from EA themselves, and save $10 if you get Crysis too). The Steam package (at least in my country) is full price, but I'll wait and see what happens next week. The game ships next weekend so maybe they'll wait for the weekend deal (which IMO would be ridiculous) or something. Or not, because you can already pre-order both so they'd just screw up like they did with GTR :P

Anyway, Warhead is already a no brainer, and after the Bionic Commando issue I'm sure there'll be more sales. I just need to see the price here in retail.

PS: The Witcher: Enhanced Edition just appeared in the Coming Soon list :) Fantastic month!

I was about to say, EA on Steam, Hell just froze over. It still says EA as publisher which is an odd thing to see.

I'll probably activate The Witcher through Steam and transfer my game save over.

EA is not involved? How does that work?

I was so excited for a minute because Crysis on Steam means Mirror's Edge, RA3, all that stuff on Steam possibly.

They really should jump on the boat though...it'd probably get them more money in the end than with their own digital downloads...but I'm sure they want all the money for themselves...

EA on Steam is a pretty huge deal. They are still publishing it, even if they didn't do the coding for it.

Pleasantly surprised to see this.

Odd since EA has its own digital distro system, even if it's not a game management/console within a box system like Steam.

EA is still the publisher; Valve only publishes its own IPs, so Steam is just the distributor/distribution service.

If Warhead has any form of install DRM, that should make it a pretty obvious choice for purchase through Steam instead.

I might get the first game now.

whats the difference between crysis and crysis warhead?

 I believe Warhead is the game through the eyes of another character. I could be wrong, though.

Yes, Tycho, the more memorable buddy...he's like Jason Statham basically.

Warhead will have more action-driven sequences than Crysis, but it's supposed to be easier on your PC than the first.

You means Psycho, not Tycho. He's the guy who shows up at the end of the game with a giant gun then goes back to "finish it."