Log Player IP and Steam ID's?

[Arjen]

There are serveral ways. All steam_id's and IP adresses are being logged in the database when you're using HlstatsX CE.
All steam_id's, ip-adresses and nicknames are being logged in the logs-dir.

Maybe this is what you're looking for (a sourcemod plugin):

http://forums.alliedmods.net/showthread.php?t=39755