Pastor Fisk has posted a great article on his blog "Babylon Falling"
Especially insightful is this paragraph.
The Biblical truth is that the manner in which Jesus told his Church to go and make disciples was by baptizing them into the faith which they would also be taught. Apart from this promise, there is no assurance that anyone anywhere will be saved. (The thief on the cross was saved the exact same way - by a direct promise from Jesus. Baptism is your "today, you will be with me.")
I can easily imagine using the account of the thief on the cross to explain baptism! This is very cool!