I was looking for an iPhone app a while ago to search Irish business phonenumbers and couldn’t find one, so wrote one myself. And while I was waiting for Apple to approve my app, a different phonebook app was released with better user interface! BUT it just searches the goldenpages website so you need a net connection. I scraped the Goldenpages website and stuck it in the app, so no net connectio needed, handy when you quickly need a number.
Check it out here, only e2.39 to buy