Tom Foster's Management Skills blog has a post on how to find a life preserver when you've reached your own personal Peter Principle moment.
Here's a look on other ways to foil the Peter Principle on How Stuff Works.
Yet more tips on how to avoid your own incompetence.
The Peter Principle revisited offers a refresher on the topic.
The Walrus and the Carpenter blog takes on the idea of the Peter Principle and innovation, which is to say that when a company has a cash cow, it ceases to truly innovate.