Key Points
> Youtube wisescreen is triggered by uploading a video of res 1280*720
> YouTube super widescreen is triggered by uploading in a video res of 1920*960
> mp4 is a good format to upload because it gives great detail at 1280*720 while still having manageable file size for uploading

my exact procedure is;
I play as 2142 at res 1280*720 [comment below]
I capture in wegame at high res mode which turns out to be res 1024*576
I edit in Vegas v6 and edit out the loud static (that wegame can insert in error) with other background sounds
I render in wmv res 1920*960 (my older version of vegas v6 does a poor job of rendering to mp4)
I convert wmv file to mp4 in mediacoder (free) at bit rate of 4200 and at double pass, it outputs at same res as input ie 1920*960
I upload to youtube and have nice crisp normal quality and great HD widescreen example


comment
copy your 2142 desktop short cut, right click properties, and add at the target line the text
+fullscreen 1 +Widescreen 1 +szx 1280 +szy 720
so from something like this
"C:\Program Files\Electronic Arts\Battlefield 2142\BF2142Launcher.exe" +menu 1
to something like this
"C:\Program Files\Electronic Arts\Battlefield 2142\BF2142Launcher.exe" +menu 1 +fullscreen 1 +Widescreen 1 +szx 1280 +szy 720

EDIT 1st oct 2009
Youtube has brought out super wide screen that is triggered by uploading a video of 1920*960
Even if you record in a lower res than this, i suggest you render to this res and upload to youtube at 1920*960
see below for pictures of the same footage uploaded at different res's, the higher res 1920*960 has a sharper picture etc, check out the blue score, top centre of the screen