perhaps best method would be using wireless connection.....You could get a wireless router and be hard wired to the router and your brother could buy a wireless card and connect to your router wirelessly....that way you both would be on the same wireless LAN.
Since distance is a factor in wireless connection then I would suggest to use 802.11N rather then A, B or G.....here is some info on 802.11n:
http://www.pcworld.com/article/id,11...1/article.html
Cheers