Left 4 dead sdk coming soon!
I know I want it.

a left 4 dead patch has come out thanks kotaku
General
- Fixed Survivors being able to climb surfaces marked for versus infected only.
- Fixed a class of SurvivorBot bugs dealing with rescuing downed players.
- Players can no longer grab ladders while flying through the air after a Tank punch.
- Shooting near a car with an alarm that has already fired the alarm will no longer make chirping noises.
- Improved loading time.
- Fixed mini-gun physics exploit.
- Fixed propane tanks (and other physics objects) causing players to fall through elevators.
- Fixed rare achievement bug issues.
- Fixed several map exploits.
- Fixed various match making issues.
- Fixed NAT traversal issues.
Versus Changes
- Added HUD elements to show status of other infected players.
- Changed color of infected player name in chat to red.
- Fixed exploit where players could spawn infected bots
- Fixed instance where a Survivor changing to the infected team would be attacked by infected bots.
- Normalized special infected melee damage.
- Made the following client commands cheat protected: "Kill" and "explode".
- Fixed exploit where infected players could run away and teleport back to gain health.
- Players can only change teams once per map.
- Players can't change teams while other players are still loading.
- Tank spawns at the same % through the map for both teams in versus mode.
- Made the Tank and Witch spawn directly on the escape route.
- Increased chance of getting the Tank or Witch.
- Fixed team swap issue.
Hunter
- Easier to pounce a Survivor who is meleeing.
- Increased Minimum damage a Hunter pounce does.
Smoker
- Fixed Smoker tongue tolerance.
- Smoker now has to be killed or the tongue destroyed for the tongue to break.
- Survivor's cannot bash someone off the tongue until the Survivor being pulled is paralyzed or hanging
- Tongue attacks that fail to paralyze or hang a Survivor will use the shorter ability delay timer.
- Fixed cases where the ability timer was not using the correct time.
- Fixed case where you could point at a Survivor but not register a tongue hit
- Fixed Smoker tongue not targeting and landing properly through PZ ghosts.
- Smoker tongue does damage every second while dragging paralyzed Survivors.
Tank
- Bashable objects now appear with a red glow.
- Tanks hitting a car with an alarm disables the alarm permanently.
- Tank frustration timer is only reset by hitting Survivors with rocks or fists.
- Reduced autoshotgun damage against Tanks.
Witch
- Witch spawns at the same % through the map for both teams.
- Avoids spawning within a certain % of the tank.
- Fixed an exploit where the Witch could be woken up and tricked into attacking Survivors.

Managed to get in a game on a dedicated server after the patch came out, here's my firsthand opinion on some changes: This is extremely nice. Shows the infected players like the normal players, and shows how long until they respawn. Nice, in theory. Problem is, where the tank (and witch) spawn now is fixed for both teams. Meaning, the first half of the match, the infected learn where the tank spawns, then can prepare for the fight when they are the survivors. Had the witch early in every map, so yeah, they definitely increased their chances. Kinda call bull on this one. Saw the same exact stuff happening as pre-patch. Saw some cases where this didn't work. The person got melee'd off the tounge almost instantly. Kinda nice, definitely would help when you're surrounded by cars and only some can be knocked around. While I understand this, it appears that, at the same time, the timer immediately starts counting down, even if the survivors are nowhere near where the tank spawns, so you can lose your turn as the tank just trying to get to the survivors.
Definitely need to try playing more, but might need to wait a few days for more servers to get patched.

just a bump with server info
l4d gog server
[url=http://www.gametracker.com/server_info/208.167.247.191:27015]http://www.gametracker.com/server_info/208.167.247.191:27015[/url]/

just an update with some personal, left4dead achievements
http://www.wegame.com/view/Zoey_Has_Startled_The_Witch/
this is something i uploaded to wegame, it has over 1k digg views and is supposedly on the first page (it's been flirting).
anyway, I hope you guys enjoy it, I'm proud over it.

How do I join the server?

Add it to your favorites, then find it in the server browser.

Left4Dead on Steam
Steam is selling L4D for 50% off.
I already have it, and so do my friends..
I'm kind of disappointed I look forward to their deals every weekend, although I've never bought one of their items during that deal.

If I'm on, I'll play ya.

I don't know if it's already commented, but here you can buy a Left 4 Dead Key for 12€
EDIT: As Weclock said is ONLY for European stam accounts.

regardless, Steam has some sort of crazy filtering system that will block out keys from different regions. :(
So unless you typically use "€ " I don't recommend buying those keys. Americans, stick with the steam sale, otherwise you'll end up buying a 12 dollar key for a european.

Oh well yeah, of course, I forgot a lot of people in here is american.

$12 < 12€ (I was going to say << but apparently it's not as much as I thought)

That's alright. :) It's the thought that counts.