Unless the steering wheel is shaking when you're NOT pressing the brakes... it won't be an alignment issue.
I'm going to lean towards needing pads & rotors... you may even have a caliper or its pins binding a little.
I'm sure if you jack up the front end, and spin the wheel by hand, you'll hear the "whoosh, whoosh, whoosh", sound due to the rotors being warped and hitting the high spots during rotation. You can sometimes see the pads having uneven wear... as in on one wheel, the one pad will be worn more on the inside or top edge while its pairing pad will be worn on the outer or bottom edge.
Keep us posted & let us know what you find... Goood luck!!
