his power states
GET IN YOUR FACE: Guy Gardner can use Charge. Give Guy Gardner a move action, and if he ends his move adjacent to an opposing character, the move action counts as a free action instead, and he uses Battle Fury until that character is KO'd.
so since the move action is instead considered a free action, would a person be able to move him and then use poison?

No. He has to be given a move action first, to "activate" the free action.

what about this bit
"the move action counts as a free action instead". wouldnt this mean that the move action was not actually given? its not activating its replacing as i read it ^^

He is given the move action but before actions resolve you check the conditions of the square he ends his movement in.

Is Guy Gardner adjacent to an opposing character? Y or N

If Y then the move action becomes a free action and no token is given.

If N then apply action tokens normally.

The beginning of your turn ends as soon as you give him the move action. Didn't matter that by the end it's free.