Prototyping is a technique that addresses some of the shortfalls in waterfall. Amusingly, other than names for things there is nothing new in agile methodologies like scrum and XP. They've been around since the early '80s.

If you're into process, try and get your hands on a copy of (it's a mouthful) -

Wicked Problems, Righteous Solutions: A Catolog of Modern Engineering Paradigms: A Catalogue of Modern Software Engineering Paradigms (Yourdon Press Computing), by Peter DeGrace and Leslie Hulet Stahl. http://www.amazon.com/dp/013590126X.