Stripping the DRM

I need to bust me some DRM.

It’s the DRM on my own work, I hasten to add.  My publishers have ebook rights for North America on some titles, but I control the rights elsewhere.  Easiest way for me to exploit these rights is to strip the DRM from the North American ebooks, then put new covers on them and market them to the rest of the world.

Anybody got a good way to do this?