is your steering wheel shaking? or the whole front? if you feel it shaking on turns then it's air in your power steering. if you feel it while braking in a straight line, you might want to recheck your installation
I haven't noticed it when I am turning, but I usually only brake hard in a straight line. It seems to be the whole front end, but of course I feel it mostly in the steering wheel. Any ideas on what I could have missed during the install?