WiFi Question

[Lienus]

Hey guys, I don't have that much experience when it comes to wifi so I thought I'd throw this out there to see if anyone may be able to lend a hand.

My niece just got me an xbox 360 and the silly thing doesn't come with wifi capabilities! (go go ps3!) I was wondering if I could use my phones wifi signal it picks up from my router to supply it to the xbox. I know I have a wifi adapter laying around here somewhere but I can't find it. I apologize in advance if a similar question has been posted in the past, I looked around the Omnia forums a bit and saw some threads about wifi tethering but I'll be honest, I don't really know what that means. Thanks a bunch for any help ya'll can offer!