Fusion Halifax's Urban Development Action Team put together a Google Map that shows all the developments in Downtown Halifax that are under construction, approved, and proposed. Check it out here:
http://www.fusionhalifax.ca/en/home/...opmentmap.aspx
If you're a keener and want to contribute the map is open to anyone to collaborate on it. You can add new developments, modify the location of the markers, and build out the descriptions of each one as they're pretty basic at the moment.
Enjoy!
Steve