Apple opened the door to its iTunes App Store for the iPad this evening, and after a fairly thorough scan, I didn't find any turn-by-turn navigation apps, or outdoor/recreational navigation apps. That makes sense, because the first iPads to be sold starting this Saturday will not have GPS chips. The iPad models with AGPS are to be released later this month, and there will be additional navigation apps released by then.
For example, Fullpower, maker the popular MotionX outdoor and auto turn-by-turn apps for the iPhone, will have its products ready for the release of the 3G + WiFi iPads with GPS, says CEO Philippe Kahn. "We have MotionX-GPS HD and MotionX-GPS Drive HD specially optimized and enhanced for the iPad 3G to be released in a few weeks with the launch of the GPS-enabled iPad 3G," says Kahn. All of the MotionX "HD" apps for the iPad will run at full screen screen size, and are designed to take full advantage of the larger platform, says Kahn. So, turn-by-turn directions on a 10-inch super high-resolution color screen are about to become a reality.
Other turn-by-turn navigation app makers I contacted weren't ready to make announcements yet, but it's reasonable to assume that AT&T will offer its TeleNav-powered "Navigator" app on the big screen at iPad 3G + WiFi release, as will TomTom and most other navigation app makers.
In addition, I consider it highly likely that the leading location-based services app makers such as Gowalla (already confirmed) and Yelp will be there when the GPS-equipped iPads hit the stores.