In reply to Chris Georg:
On behalf of the groom thank the guests for making the effort to share in the special day etc.
Thank anyone who assisted in the weeding, eg bridesmaids etc
Make some compliments about the bride, eg
The bride looks stunning, the groom looks stunned,
The bride looks one in a million, the groom won in a raffle,
Tell a few embarrasing stories about the groom (but not the occasion where he puked over the whore he was shagging).
Round up with a couple of stories about what a throughly decent chap he is.
Sit down.
Aim to talk for 3 - 4 minutes.