Unfortunately there is no way to launch the Bing Maps App from within your own application.
In an early CTP there was a way but this has been removed. Hopefully it will return in the future but it is not on any current, public, roadmaps.
This leaves two alternatives.
Option 1
You could perform a search for the lat/long you want to show. The search app does directly integrate with the bing maps app so, assuming that bing can take the lat/long you provide and return something useful, the user would still be able to do whatever they wished within the bing maps app.
This has 2 downsides though. Firstly, you have no control over the search results. And, secondly, you cannot test this on the emulator.
Option 2
You could use the BingMaps control within your own silverlight application.
(Prior to the RTM, it was posible to use the full Silverlight version of the control within your app. But, this had a few quirks and was only ever intended as a stop gap solution.)
While not as fully featured as the app, the control does offer a lot of functionality.
Without a real device, but you could simulate location data, for testing, with the Reactive Extensions.
Even with a real device you will probably want to look at doing this as it's a lot easier than trying to debug while walking or driving around.