Likely the fan bearing bracket... although the air pump idler bearing also seems to have a low expected useful life. Check the fan from the side, the blad should not wobble fore/aft, if it does then you MUST get the bearing bracket looked after SOFORT! Failure of this bearing will almost guarantee the additional cost of a new radiator, belt, and fan (and likely a tow too).

Another rule of thumb... if one of the other idlers goes wobbly, the others will not be too far behind. Once you have the belt off you are best to replace them all... including the AC clutch bearing which you wil need specialized tools to get at (Autozone might have them for loan).