Not sure what you mean? Record it... go to your youtube account (top right corner) select upload, then browse for the file, and upload it.
With CoD Black Ops and MW3 you can do it through file share however the quality is shocking. Buy a HD PVR if you want perfect quality.
HD PVR, is video recording device you plug into your tv. It's overrated. They are overpriced. You can buy a dazzle, and get 1080 quality, unless you're retarded.
The dazzle is a device that has Video input on one side and USB output on the other side. That way you can plug your xbox into it, and plug the dazzle into your comp, and record. An Hauppauge HD PVR is basically the same thing, but it can record in full HD while the Dazzle can't.
The irony of this post is shocking. You can't get 1080p quality out of a device that only accepts up to 480p input. If you think that upscaling 480p video to 1080p quality is the same thing as recording in 1080p then I'm sorry to be the one to tell you, but YOU'RE retarded. OP, I would recommend a Hauppauge Colossus if your computer has an open PCIe x1 slot. It's what I use and the quality is superb (plus it's only $150 compared to $200 for the HD PVR / BMI Pro). If you want to check out my quality, my channel is www.youtube.com/recedinghairlineman
I'm about 99% positive that there are no Dazzle capture cards with anything other than a composite input, which only works at a maximum of 480i. Unless you're using s-video, in which case if you think 720p s-video is comparable to 720p component/HDMI you are sorely, sorely mistaken. Link me to a sample of your video quality so I can compare it to my 720p via component and there will be an obvious difference.
If your clip is 30 seconds long or less (or 1 minute or less if your Elite Premium) you can upload it through rendering it and uploading through Elite. Firstly, link your Elite account with your youtube account (if you're unsure on how to do this, youtube it) then once thats done, go to your fileshare, get the video you want and choose the option "Render". It will then go straight to your Youtube channel. EDIT: This is for Call of Duty: MW3