To find your steamID you need to bring down console in game (doesn't amtter whether it's snigle or multiplayer) and type "status" without the " and copy the full line where you see your name.

example...

# 1234 "Your Name" STEAM_X:X:XXXXXXXX 1:38:00 68 0 active

Go into notepad or wordpad and paste the line that you copied. Your steamID is the part of the line that is in bold above.

why would u need your steam id?

Because people say yes to competing in tournaments, but when actually asked to do something themselves... create an account on ESL for example, they suddenly become sloth-like at best.

To enter ESL requires a team, enough members and all members to provide a steam ID... I thought I'd pre-empt the 'how do I find my steam ID?' question

ohhh. ok. was just wondering.

for example mine produces:

# userid name uniqueid connected ping loss state rate adr
# 2 1 "=SM= MonkeyFiend" STEAM_1:1:123456 00:15 41 0 active 30000 loopback

where the 1:1:123456 is my steam id