As far as i know there are three major regions for XBOX 360 console
NTSC/U
NTSC/J
PAL
The most rare of these regions is NTSC/U as far as we are concerned, MOST of the games available ARE region free but than there are few exceptions.
@Sub7er i don't know what they are teaching you at microsoft but it's hilariously wrong, only ps3 games are region free but ps3 is region locked for bluray movies, xbox 360 has always been region locked and its upto devloper/publisher to release games region specific or region free, one prime example is this release of Forze 3
Forza Motorsport 3 (c) Microsoft
iNFOS: Rel.Date: Oct/09
Platform: X360
Region Free: No (PAL)
Genre: Action
Languages: English, German, French, Italian, Spanish
Format: dvd
Size: 2 DVDs
The above was for the PAL (Europe) release while the following is from the NTSC(U) release of the same title
Release #: 1
Game Title: Forza Motorsport 3
Publisher: Microsoft (Micro$oft)
Developer: Turn 10
Disc #: 2
Region: USA (NTSC)
Coming back to the topic, if you download games and burn them yourself than 95% of the times it doesn't matter which console you have go for the cheapest, most of the titles locally available are NTSC/J or region free and thus shop keepers often fool you by saying "Sir this console is region free"
hope that clears the confusion 