From today's PG:
The article states that goals of the Pittsburgh Promise include "luring people back to the city after decades of neighborhood decline and spurring neighborhood revitalization," and that the Promise's executive director has stated that he wants to stop the population decline by 2012.
However, as has been noted in other PG articles, the rate of population decline has slowed and demographers are predicting a leveling of population. State department of health data shows live birth rates leveling off after 2001. So, Promise or not, it seems that Pittsburgh's population level is stabilizing.
For many people, though, the need to pay city taxes remains a great deterrent to living in the city. City taxes are not likely to be lowered until non-profits that operate similarly to for-profit companies pay taxes more like those for- profit companies.