Tribeca Film Festival isn't coming up for another month (April 23-May 4), but as I was doing some research on the site, I found out you can watch the complete collection of shorts from last year on their site: http://www.tribecafilmfestival.org/videos/?mCat=180252 They cover a range of topics and range from roughly 2 minutes to 30 minutes.

Last year's best documentary short award winner at Tribeca was, "A Son's Sacrifice" by director Yoni Brook. From the ones I watched, I really enjoyed Annette Apitz's "Warm Comforting Home," a 3 minute documentary about her relationship with mother created from 1960s era home movies of the director as a child.

Sundance also streams a much smaller selection of their festival shorts at http://festival.sundance.org/2007/watch/index.aspx?guide=documentaries.

Both of these sites offer a great way to watch some of the best shorts out there--at your convenience. You should check them out!