you *must* use the best five cards. so the ace is the kicker.

player 1 shows
6h, 6d, As, 10d, 8h

player 2 shows
6c, 6d, As, 10d, 8h

another case is when the board is:
Ace King Queen Jack Ten, hearts. dosn't matter what the players cards are, it's a split pot.