Did you use Windows Movie Maker or did you upload it straight from your camera? If you upload it to your computer, you can transfer it to Windows Movie Maker. Windows will make clips. You drag the clips into the story board. You can then right click on each clip and select "slow down half" (it says something close to that). Save the project as a wmv. Well if you're satisfied with it save it as wmv. If not, you save it as a project file. Then go to youtube, click upload, it will ask you to name the file and to give a little synopsis, click next or whatever, and it will ask you to browse for your file, find it and click it. It will start uploading...
I haven't uploaded video straight from my camera to Youtube. I'd have to look it up in the "help" section on Youtube to find out what the bug is.