[whshep]

I don't know of one, but I agree that we need one (like the up-down arrows in iCal, or the +/- in some finance apps).

In the interim, you can use 1d to increment one day, 2d for two, -3d to decrease three days, etc. Also works with "m" for month, "y" for year, "w" for week. Pretty cool, though I'd like to have the option to zip through dates by holding down a single key.