First off, I'd suggest you check and make sure none of the under panels are lose.
If they are all in place, I'd suggest you take the front wheel off and check the brakes (maybe a pad or the caliper got knocked lose).
If that don't work, I'd take it into a brake/suspension/front end shop and explain what it's doing and ask them to fix it.
Who is ol humfrz trying to kid - I'd just do step three, while I sat in the waiting room and drank a cup of coffee and read a car magazine -
humfrz