Well, you can click on the value listed next to the dial and type in a number directly, but to my knowledge that's about it as far as keyboard manipulation of posers parameter dials.

The only other "keyboard" responses of note here are the up and down arrow keys, they will allow you to cycle through the chosen parameter for your parameter dial, IE, if you have the Body of a figure selected and hit your down arrow key, it will go to the next body part listed in the heirarchy (such as hip, abdomen, etc..) and you can keep cycling through till you get to the desired selection on the parameter dial screen.

Works for lights and cameras as well, BTW.