I want to know how can I make HD Videos out of a picture and music to upload to YouTube. I find ways to do it with Windows Movie Maker but on my Windows XP it never gives me an HD option.
Yes, like it's been said here, 1280 * 720 is the resolution to go for. Another thing you can do is before you publish your video, try going to Tools in the menu bar in WMM and press on Options > go to the Advanced tab and see if there's a 16:9 option for aspect ratio.
Following video explain how to make/save Windows Movie Maker videos in HD (High Definition) format.
I don't think there is an HD option- it is just based on the resolution and settings of the video. Since you are making the video from pictures I think it is just a matter of the pictures resolution. Make sure the pictures are at least 1280 by 720. Frame rate should be 24 fps or better.