WC,
Streaming movies takes a lot of network bandwidth, to try to do it succesfully over wireless is very difficult unless you happen to be in the same room, and then you'd plug a cable in
I have a Netgear DG834GT router as the wireless point in my network which is capable of 108mbps, but I can be two rooms away on the same floor and struggle to get 54mbps, I have to say IMHO wireless is still a bit gadgety, and I only use it on very rare occaisions usually to show someone how poor wireless is. I could'nt rely on it for my business network it drops out, stops working, falls to horrendous speeds, it's still way too unreliable.
I have spent a lot of time and money

getting a set up that can stream ripped dvd files, I run a full gigabit network between all my PC's the DG834GT is my internet connection, firewall, 100T connection for print servers etc and my wireless point. Everything else is connected via a gigabit switch. I can stream .vob files without any hiccups, the high def stuff that I have is still a little sluggish but is watchable, watched Gladiator the other night and it just stuttered once. Try downloading VLC media player from
http://www.videolan.org it's a great, simple non flashy free

player and will play anything you throw at it, it's also designed for streaming movies so see how you get on. But after lot's of tweeking and trying and banging of head on walls, my advice is to forget wireless it's just not fast enough or reliable enough, the technology needs to come on a lot before we can have fully wireless networks, if you can run a cable then run a cable it'll be much less frustrating.
good luck
Wilbur