quick XBOX question
 

are there such things as firmware/software upgrades?

firmware, don't think so.
Software, yes
Dead or alive already had an add on. If you have the original game, you can get upgraded costumes and stuff.

Pretty cool, I think.

how would I go about doing that
after I have hook up XBOX to my dsl switch

There isn't a particular site per say, that's what I think your trying to get to.

The update came in the form of a CDrom
the disc comes with the OXBM Official Xbox magazine.

I'm sure though in the future, they will be online via Xbox live.