I read somewhere that is possible to obtain the XBox SDK to develop games for this console. Anyone of you know something about that? How does it costs? Is it necessary to work in a game-developing company to get it? Do you have to sell your soul?

The professional SDK costs quite a bit, I want so say somewhere in the range of $30,000 (that was a number I heard a long time ago.)

There are independent developer programs though, more info at:
http://www.microsoft.com/PressPass/press/2000/Nov00/XPKPR.asp

Selling your soul isn''t necessary, but may help

Thanks a lot.
I work as a programmer, but not in the game developing area, so I wasn''t sure if I could get the Xbox SDK...
I love programming games, but for now is only a hobby.
I don''t want to spend 30,000$... but I''d like very much to develop an Xbox game on my own =).