Some of the broadband routers have the modem built-in. If your friend already has a modem that has a network jack on it, all he needs is a standard broadband router.
My experience with wireless routers is limited, so I don't know of a specific router to recommend. I don't recommend that you get a D-Link router however. I have worked with a few different wireless D-Link routers, and they have all been terrible (their firmware always seems to have major problems). I had really good experiences with wired Linksys routers, but that doesn't say anything about their wireless products.