Shield Proficiency [General]
Benefit: You can use a shield and take only the standard penalties.
Normal: When you are using a shield with which you are not proficient, you take the shield's armor check penalty on attack rolls and on all skill checks that involve moving, including Ride checks.
Special: Barbarians, bards, clerics, druids, fighters, paladins, and rangers automatically have Shield Proficiency as a bonus feat. They need not select it.
Source: SRD 3.5 Feats