Making file ready for YouTube

I’ve made several animations (very noobie no doubt) I just don’t really know how to save files so they look right. SWF look great but I can’t further edit them. For me avi or wmv look pixelated. Any suggestions on how to get an animation ready for youtube? Or windows movie maker?

Please have a look here:

http://www.lafcpug.org/Tutorials/basic_you_tube.html

Cheers
Nolan