A more structured and detailed thread than the sticky - this is no diss, just an attempt to make it a bit easier to look and find people to play with on the Xbox 360.
Just put your GT and at least Region/Country and Spoken Languages down, the rest is voluntary.
Here's mine (below is an empty template to copy/paste):
Gamertag Xbox Live: P4NCH0theD0G
Languages: English, German
Online-Times: differing, mostly from 18:00 - open end (CET = EDT + 6 hours)
Hope to see you online:
And here's the template so you can just copy/paste and input your info:
Gamertag Xbox Live: