No, I don't youtube.
Max file size for DVD Video = 1GB -> it's possible that the video you'd like to share is spread over more than one VOB file ( http://en.wikipedia.org/wiki/Vob ). Then there's youtube's 10-minute length limit, etc.
My advice: rip your DVD's content (assuming you're talking about Video-DVD) to hard-disk (programs: dvddecrypter, dvdshrink, ...), convert those VOBs to AVI (program: dvd2avi), edit the AVI(s) (set start/end, resize, append AVI, etc.; program: virtualdub) and save. Now convert to target format (mpeg4, flv?) with this converter: http://www.effectmatrix.com/total-video-converter/index.htm.
According to youtube 320x240 would be best:
Enjoy.
P.S.: Most or all programs mentioned in this post are freeware. I assume you're using MS Windows.