Concentration Spell

 
Prerequisite(s): Spell Caster Level 1+
 
Benefit: You can maintain a spell with a duration longer than one round through concentration. You must start concentrating right after casting the spell, and, for as long as you keep it up, need not count time off the spell’s duration. After you stop maintaining the spell, it’s normal duration resumes and then terminates as usual. You cannot use this feat to maintain a spell past ten times normal duration nor can you resume concentration. A Concentration Spell uses up a spell slot one level higher than the spell’s normal level.
 
Source: Complete Divine