How come my videos recorded from my digital camera can only be uploaded to video sites if theyre shortened?

they only fit if i limit them to about 30 seconds when other peoples videos can be 4 minutes plus. is this just my camera? its canon sd630

Set your camera to 320 x 240 @ 30/fps. That will make the file much smaller and while it will be much lower in quality than when you shoot using 640 x 480 @ 30/fps.

take a smaller size video
you are using the large video size

Try this one.

http://video.vdownload.org/