I just purchased the new Canon SX30 IS after viewing video samples on youtube and tested it out yesterday using the full 35x optical and 4x digital for a 140x (3360mm 35mm eqiv ) and the IS worked very well for such a low priced camera IMHO.
YouTube - Handheld test of Canon SX30IS @ 35x optical + 4x digital zoom (140x) 3360mm (http://www.youtube.com/watch?v=XMTjK5caLcA)


Blimp at sunset with Canon SX30 IS at 35x zoom (840mm ,35mm eqiv) handheld.
YouTube - Blimp at sunset with Canon SX30 IS at 35x zoom (840mm ,35mm eqiv) handheld (http://www.youtube.com/watch?v=KfwA15dgqJQ)

First handheld test of my Canon SX30IS with 35x optical + 4x digital zoom (140x) 3360mm (35mm eqiv) of the moon.
YouTube - Moon handheld test of Canon SX30@35x optical + 4x digital zoom (140x) 3360mm (http://www.youtube.com/watch?v=NxSKiBhE83c)

The OIS is quite amamzing for such a long range. These less expensive cameras are getting better and better.