Hi,
Since you can't upload your replays directly through xbox live, you'll have to use a different method which I show here. There are a few different methods, but I'll show you one of the most common ones. Please note that this method won't record in HD.
*YOU MUST INSTALL THE SOFTWARE THAT COMES WITH THE DAZZLE FIRST BEFORE DOING ANYTHING*
You'll need the following
Dazzle DVD Recorder - $50 from Best Buy/Circuit City (comes with software)

2(or 3) RCA Y-Cables - $3/each (for audio and video)

12ft double sided RCA Cable (which I stole from my DVD player)

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What you want to do first is plug in the two Y-adapters into your TV. You can put one for audio (white) and one for video (yellow). Like so

Make sure you take your RCA Cable and your Xbox 360 cable and plug into the corresponding slots. The two yellows will be on the same cable, and the two whites will be on the same cable.

It should look sorta like this

Now you take the other end of your RCA cable and plug into the Dazzle.

Now you connect your Dazzle to your Laptop/Computer

Assuming you've already installed the software, you need to open up the video editing program that captures the video. You can use Windows Movie Maker for this part, but I'll be using Studio 10.
Open the edit tab
Your game should be playing in the top right corner. Hit "Start Capture" to start recording

Once you're satisfied, "End Capture"
Now you can go edit your video by going to the 'Edit' tab

Once you're done, go to the "Make Movie" Tab

Save...

Upload to a vid hosting website (youtube, metacafe, etc...)
*Quality varies depending on which site you use
Hope this helped. Post a comment if you have any questions, or if I forgot anything.
Enjoy
even if your in a Benz you still a *** in a coupe.
-Kanye West