Signing up with a Pittsburgh-local ZIP code should get you in–go to http://www.endomondo.com/campaign/national (and maybe hit ‘Local’ in the upper left), and you should see the Pittsburgh info. The FAQ link on that page is for the national campaign; scroll down for info from BPGH (on the right) and some conversation (on the left), both of which may help clear things up.
To see how you’re doing, go to http://www.endomondo.com/campaign/national/leaderboard and hit ‘National’ in the upper left (holy crap, I’m 476 in the country? whaa!?); hit ‘communities’ to see how Pittsburgh (#136, 160.42 p.) compares with elsewhere. Hit the ‘show’ dropdown to restrict to large (‘Class I’) communities–we’re still #3, behind Madison and Lincoln NE, but way ahead of #4 Milwaukee, with #7 Cleveland barely in sight. Go back up top and hit ‘Local’ to switch to seeing how you’re doing in Pittsburgh.