I've heard people say you don't have to sanitize the vanilla beans, but I would. However, you don't need to use a pressure cooker. Split the beans lengthwise, scoop all the stuff out, and throw the whole lot of it into a small ball with some vodka (or your rum, if you prefer). Give it about 12-24 hours, and dump that in with your oak chips.
Brody's Brew House
Primary: Spiced ale
Planned: Butternut squash & gala apple harvest ale; brown ale or porter; barley wine
In the fridge: Dogfish 60 minute; Imperial Stout