Yeah, actually I have the original Xbox, and I bought the wireless receiver for it, which is a receiver, and has an Ethernet cable that can be plugged into the back of the xbox... it also came in handy when you need wireless on a computer as well. I bought mine at Best buy, and it is a the X box Brand.
It's hard to find now... but I found it online at COMPUSA.com : http://www.compusa.com/products/product_in...ireless_Adapter
THis is exactly what I use... As long as you have a good connection, like cable, or the higher end DSL, then you shouldn't have any problems.... You do need a Wireless router to use this though. I use Linksys Wireless g/b router, and it works wonders.... I hardly get lag, and I have never lost my connection.
Setting it up can be a lil trouble, but it's not too hard to figure out, just fallow the instructions that come with the receiver.
Hope this helps, and good luck