I have spent a few more hours on Go a2b and things have progressed further. Routing is working. I have got map rotating correctly. There is an issue with zooming in and out but i am looking into it.
Currently supported maps are Bing and OpenStreetMaps. Gonig to add Google and Yahoo before beta 1
After beta 1, i plan to get TTS and HUD working correctly.
please contact me if you wish to take part in the beta and help me get it right.