Looks like the pre-order for Half Life 2 is going to be on Steam tomorrow. Steam is valves online delivery system, ie: you buy a game online and it's downloaded to your computer, so all updates, etc are done online automatically.
Anyway, the pre-order is going to be up on the steam system tomorrow, so you can get a variety of options, from HL2 and CounterStrike: Source to HL2, CS:S, Half Life 1: Source, t-shirts, etc. Of all of this the only thing actually available now is CounterStrike: Source though. Wonder if this is marketting hype to get people ready and bought in or if they are actually close to releasing HL2... course, if they were close they'd keep their mouths shut and not piss people off by making them pay for something they can't get right away :)