Tower Shield Proficiency [General]
Prerequisite: Shield Proficiency.
Benefit: You can use a tower shield and suffer only the standard penalties.
Normal: A character who is using a shield with which he or she is not proficient takes the shield's armor check penalty on attack rolls and on all skill checks that involve moving, including Ride.
Special: Fighters automatically have Tower Shield Proficiency as a bonus feat. They need not select it.
Source: SRD 3.5 Feats