http://kotaku.com/5131676/left-4-dead-patch-now-live

No new maps but some of the nice improvements ares:

Tank spawns at the same % through the map for both teams in versus mode.

Hunter is now easier to pounce a Survivor who is meleeing.

Smoker tongue does damage every second while dragging paralyzed Survivors.

Witch spawns at the same % through the map for both teams.

Lots of other good improvements in there too. Sadly the mini gun physics exploit has been fixed.