Palm's new Centro device is designed to attract younger, less wealthy users, but its Palm OS software is a major drawback. It is basically a smaller version of the Treo 755p, with a tiny keyboard arranged in straight rather than curved lines that can be awkward to use. The price can be as low as $100 with certain contracts and after rebates. Palm OS has not been radically overhauled for over five years, and is no longer competitive with other smart phones. Among its problems is the fact that it can only do one thing at a time, and lacks built-in Wi-Fi and GPS navigation. The web browser is quite difficult to use, and many users find it crashes frequently. The problems with the OS can be linked in part to problems with the development of the Foleo device, a project that was killed only days before the device was due to launch. A new OS based on Linux will not be available until the end of next year. Still, Palm has the best and simplest user interface, as well as the best integration of PDA and phone functions. Apple's iPhone does not offer a simple way for users to look up contacts, though its browser is much better than Palms's. Research in Motion, in contrast to Palm, has released a number of new BlackBerrys, and Microsoft has improved the usability of its Windows Mobile. In addition, at least one new version or Windows Mobile will be released before the new Palm OS, and perhaps even two. Palm also offers Treos running Windows Mobile but the handsets are not as stylish as those offered by competitors such as Samsung and HTC.