How do i play XBOX 360 in HD?

As long as you have the proper cables it is completely dependent on the TV. The Red green blue cables defiantly allow for 1080p. So if your TV supports 1080p then it may be as simple as going into your display setting on the xbox360.

However if you want 1080i you will need to purchase the HDMI cables.

Here is a guide from Microsoft on how to set it up...
http://support.microsoft.com/kb/906663?sd=xbox

Hope this helps. =D

I got it to work at 1080p thanks (: i just had to turn it on from TV to HDTV   i thought 1080p is better than 1080i why would i need a HDMI cable to play in 1080i, anyways thanks for the answer  

yeah you are right P is better than I; I don't know why I thought it was the other way around and as for the connection type HDMI and component, there isn't a whole lot of differences, and it really depends on your tv, and source device, in somecases HDMI may look better and other cases Component look better, (did not know beforehand).

I read an article (below which explains the differences, or lack of) and thinking about how much I've paid for HDMI cables I feel I've made an expensive mistake, as component cables will do the job just as well, the only real advantage I can see is audio.

anyways, great that you got it working, enjoy gaming in 1080p. =D

http://forum.ecoustics.com/bbs/messages/34579/122868.ht...

it gets ugly in 1080p because upconverting and some studios require you to watch 1080P video in an HDCP compatible connection which of course requires and HDCP cable and display. SO if you wnted to upconvert your movies you would need the VGA cable as the composite (red blue and green) wont allow you to upconvert. I have the HD-DVD player and don't know if the normal DVD player on the XBOX 360 supports upconverting. I think it does via VGA cable, but i dont know for sure.

HDMI is a lot better then component because it's analog and HDMI is digital but you can get a $6 high quality HDMI cable on Monoprice.com.

whooleo is right. The original signal from the Xbox 360 is digital, but when through component, it has to convert it to analog, which can result in noise. You really only notice it on certain screens containing black or dark colors. I always see it when loading areas on Red Dead Redemption. If you don't mind that, and you TV will take 1080p through component (some can't) then you should be fine. If you ever want better sound you'll have to use the optical port on the Xbox 360 S or on the Xbox 360's Component HD AV cable, to get 5.1. Using the HDMI will give you 7.1 to whatever you hook it up to.