I've had a similar problem in one of my Taxi's, like other above have said it could be your pads, but also check that one of your wheel bearing hasn't seized! If it is the bearing, you will need to change the suspension upright.
Good luck and hope it's only the pads.
"Give me any task to do, and I will find something else to do in it's place." Plato - a definition of procrastination