Okay, so I've just started figuring out how to make the kinds of "thingymabobs" I've seen other people make.... lol! I know there are several different websites for making these, but I use mybannermaker.com (as shown on my banners on my profile.) You choose a picture from your computer, set it as your background, and then it gives you a link to copy and paste. I have yet to find out how to make the moving ones... like from a video clip... but just to let you know cause i saw another blog about how to do it on the user blogs. I hope this helps.
P.S. Can anyone tell me how to do the moving ones? Thanks for the help!!