I'm planning on building a Gish for the next game I play in, and I was wondering how to best plan the build. I want power attack so I can do damage in combat, and I want to wield the weapon two-handed to get the most out of it. However, I need a free hand to cast spells.
The plan is to get a Scimitar (love the crit) and wield it in battle. One round, cast a spell (Glitterdust! you're now blind and I shall hit you!), and next, move up and smack him hard across the face with the sword. Again, I just need clarification on how/when I'm able to switch from holding the sword one-handed (so I can cast) to holding it two-handed (so I can kick $%%), so if crazy things like opportunity attack come into play, or immediate/swift spells, I know how to maximize my power attack.
I am looking for RAW (Rules as Written).