there are various techniques you can use to blur the water or more slow down the flow of water.
The easiest is way i have found is using the aperture priority mode and shutter priority mode of the camera.
There is a really good video tip here :http://www.dslrtips.com/workshops/How_t ... ater.shtml
Take some time and practice with a running tap at home or with a local river before you get to the waterfall or water scene you wish to photograph.
Hope that helps.
Canon 550D, Canon EFS 17-85 IS USM, Canon EF 75-300 IS USM, Canon EFS 10-22mm USM, Canon EF35mm F2.
Got some of the gear but really still no idea...