Front end noise on a C240 4matic (W203)

[SnowCub]

I got a frantic call tonight from my mother-in-law. It seems that her 2003 C240 4matic (~70k miles) is making a horrible metallic noise that seems to be emanating from the right front wheel. It only happens after the car is warmed up, like 25 minutes into a highway drive and then continues for the rest of the trip If she then parks it and the car cools off, the next time she drives it the noise is gone. If the trip is long it starts to occur after the car is warmed up, etc.

Anyone have any ideas of what to check? She wants to give me the car for a few days. I figure first thing to do is pull the wheel off and make sure everything looks ok and there are no wrips in the bushings and what not. Where should I go from there?