Xbox 360 - How do I enable HD output in the settings menu?

[SkScotchegg]

Hi there, please can you help me by telling me where I can enable HD output for HDMI in the xbox 360 settings on the dashboard.

I worked out how to do it on the PS3 but not on the xbox 360, theres nothing that says "output to HDMI" or anything that says "HD" on it.

Thanks in advance

 

[SkScotchegg]

Which resolutions are HD?

I dont think my xbox has an HDMI port, can I buy an adapter or something or do I have to sell my xbox and buy an elite?

Thanks in advance.

 

[SkScotchegg]

To clarify my xbox 360 doesnt have an HDMI port, so does that mean I have to buy this special lead from microsoft? any chance of name for this special lead or a link if a link is aloud?

Thanks in advance