You can't cast a spell during a charge.
You could touch a person if you were holding a charge for a spell like shocking grasp because it's an attack and the spell was cast before the surprise round.
Readied Actions occur before the action that triggers it...
Regarding Flatfooted:
From the SRD Wrote:Attacking on a Charge
After moving, you may make a single melee attack.You get a +2 bonus on the attack roll and take a -2 penalty to your AC until the start of your next turn.
You could touch a person if you were holding a charge for a spell like shocking grasp because it's an attack and the spell was cast before the surprise round.
Readied Actions occur before the action that triggers it...
From the SRD Wrote:Readying an Action
You can ready a standard action, a move action, or a free action. To do so, specify the action you will take and the conditions under which you will take it. Then, any time before your next action, you may take the readied action in response to that condition. The action occurs just before the action that triggers it. If the triggered action is part of another character’s activities, you interrupt the other character. Assuming he is still capable of doing so, he continues his actions once you complete your readied action. Your initiative result changes. For the rest of the encounter, your initiative result is the count on which you took the readied action, and you act immediately ahead of the character whose action triggered your readied action.
Regarding Flatfooted:
From the SRD Wrote:Flat-Footed
A character who has not yet acted during a combat is flat-footed, not yet reacting normally to the situation. A flat-footed character loses his AC (if any) and cannot make attacks of opportunity.
