TeamXbox give us the details and review on the 360 VGA cable.

Different from the HD cable set, this cable has a vga output for using with a computer monitor or other display that accepts VGA.

The resolutions available through this cable are:
640×480 (4:3) VGA

848×480 (16:9) Widescreen 480

1024×768 (4:3) XGA

1280×720 (16:9) 720p

1280×768 (16:10) WXGA

1280×1024 (5:4) SXGA

1360×768 (16:9) WXGA

Notice there is no 1080i listed - to get that res, you’ll need to HD cable.

Overall Rating: 9.1/10

The Bottom Line
“If you have a PC monitor, the Xbox 360 VGA HD AV cable is a must have accessory. For the first time Microsoft is offering a first-party VGA cable that directly takes the raw AV data from the AV port and outputs to VGA. In the past we had to rely on third-party transcoders that would transform the component video into VGA, which implied an additional transformation of the original signal.

This time, the VGA signal comes directly from the console just as the rest of the video signals provided by the composite, S-Video and component cables.

The quality of the cable is good, the length is long enough for the majority of the setups, and the fact that the cable includes both surround sound and stereo outputs, makes this AV cable a great peripheral that is suitable for many users.

We welcome Microsoft’s decision to offer a VGA first-party cable and we hope this is the first of the many cables that the company makes in response to the consumers’ petition. Now the only thing we need is a DVI-HDMI cable and you won’t hear our cries anymore, Bill.”

TeamXbox Review - Via 360 Insider