Suppose I cast a touch spell and then use a spell-like or supernatural polymorph ability to change shape. Am I still holding the charge?
Round 1: Druid casts cure moderate wounds, but doesn't touch anyone.
Round 2: Druid wildshapes into a bat.
Round 3: Druid flies up to ally and touches them to discharge the spell.
Using supernatural abilities doesn't discharge a touch spell by the rules (although a GM wouldn't be totally crazy to rule that this is similar enough to casting a spell that it should apply.)
It seems unlikely though that your friend who needs cure moderate wounds now, will appreciate it getting to him in three rounds.