An Xbox 360 would probably be the easiest to hook up, assuming your ISP carries the espn3 service.
It has wifi built in so you don't have to run network cabling and there's no worries about the
hardware being fast enough to do good video. Get one without a hard drive if you don't care about
games.
Most any recentish laptop would work too. Could use espn or the direct
usopen.com site with that.
Or most any other service for that matter.