Mobile Spellcasting

 
Prerequisite(s): Concentration 8+ ranks
 
Benefit: You can make a special concentration check (DC=20+spell level) when casting a spell. If the check succeeds, you can cast the spell and move up to your speed as a single standard action. If the check fails, you lose the spell and fail to cast it. You still provoke attacks of opportunity. If you are casting defensively, the DC increases by 5.
 
Source: Complete Adventurer