Spotting one new business idea is good. Spotting two new business ideas working together is even better. Last month, we wrote about Peasy, an online exchange for parking spaces. A very similar British service, ParkAtMyHouse.com, also lets people rent out their private parking spaces, and recently partnered with ZipCar, a company we first featured back in 2003. With about 80,000 consumer and business drivers, ZipCar is the world’s largest and fastest growing car sharing service. Founded in the United States, ZipCar recently launched in London, which will become the hub for the company’s expansion into Europe.