Just as a reminder (and this might be news for a couple of people), you can actually get better bus info from http://maps.google.com than you can from Port Authority's website.
1. Go to http://maps.google.com
2. Type in an address in the search bar
3. Use the "+" by the slider to zoom in a notch or two. Little bus stop icons appear.
4. Hover over a bus stop icon and its name appears.
5. Click on it and live bus trip info appears.
6. Click on one of the boxes with the route ID in it and get even more info.
This works for lots of cities, not just Pittsburgh.
Thank you, Google!