Coup de Grace: As a full-round action, you can use a melee weapon to deliver a coup de grace to a helpless opponent. You can also use a bow or crossbow, provided you are adjacent to the target.
You automatically hit and score a critical hit. If the defender survives the damage, he must make a Fortitude save (DC 10 + damage dealt) or die. A rogue also gets her extra sneak attack damage against a helpless opponent when delivering a coup de grace.
Delivering a coup de grace provokes attacks of opportunity from threatening opponents.
You can’t deliver a coup de grace against a creature that is immune to critical hits. You can deliver a coup de grace against a creature with total concealment, but doing this requires two consecutive full-round actions (one to “find” the creature once you’ve determined what square it’s in, and one to deliver the coup de grace).
I'm inclined to say "No".Murrdox said:Does a touch attack count as a "melee weapon"?
Are you sure?MatthewJHanson said:It is a weapon-like spell, and I tend to say you can do just about anything with a weapon-like spell that you could do with a weapon.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.