I had been trying to sweep on bass for a long time and tried all manner of crazy methods, from huge Wooten style double thumbs to changing my usual fingerstyle for a pick, none of which were entirely successful. However, Pat O'Shea's excellent lesson on this site
http://www.activebass.com/default.asp?src=l&l=22743&p=1 showed me a way of sweeping on bass much more effectively and I've now utilised it into my playing. In this lesson I hope to get people started on sweeping.
A few things to note... this technique takes some time to get the hang of, build up speed slowly using a metronome and make sure you can hear all the notes clearly. Also your index finger is going to hurt like mad after a while so don't damage it and as with anything on bass, stay relaxed... you don't want to get tendonitis! Let's start.