Brush size and my tablet

for some reason I cannot find where to change the brush size....is there a
way.  I can't believe something like that would be left out.

Also on an unrelated note, my JamStudio Tablet isn't working

http://vertexpc.com/catalog/popup_image.php?pID=103

It did work on 1.3, but now it "freezes" the open document not allowing
any kind of selecting or drawing, even with the mouse after I try with my
tablet.

I'm currently running Gimp 2.0-pre2 on XP pro

thanks