I'd try it, and see how it works. You can test it on youtube or any other video before the US Open. You can share your whole desktop on the Apple TV if the indivdiual program you are using to view the video does not support displaying its own contents on the Apple TV.
I have a late 2011 MacBook Air and a 2nd generation Apple TV, and an all 802.11 N network at home.
I've had intermetten success with streaming videos from my MacBook Air to the Apple TV. I've had lagging issues. Even streaming iTunes music to my TV (for the speakers) has had occasional lag issues. I'm fairly Apple savvy, and haven't been able to figure out why this is happening. I never run any firewalls on my Macs, so its not that.
Anyway, it was so hit or miss for me, that I gave up on it, and use a wired HDMI cable now. It works perfectly 100% of the time. You can mirror your desktop, or use the TV as an extended display.
By the way, to get the cables for anything and everything computer and AV related, go to
www.monoprice.com They have great prices, at like 1/10th of the store prices. They also have an HDMI cable that is about 1/4 the thickness of the regular HDMI cable. Its about double the price, but helps a lot when you have a 15' long cable. If you go the cable route, get a 15' long cable, so you can still sit on the couch with the computer while it is hooked up to the TV, if you want to type or anything like that.
This is a 15' super thin cable.
http://www.monoprice.com/products/p...=10255&cs_id=1025503&p_id=9429&seq=1&format=2
I really like the thin cables, as the thick ones seem to put a lot of strain on the computer's port. They really are heavy. The way they are so thin is the regular ones support communication both ways on the cable (duplex). The thin ones support communication only in one direction (simplex). This works fine for what you want to do, but would not work in applications requiring two way communication between two devices.