According to the Inside Dope blog, a Chicago based pro-choice political action committee, Personal Pac, were the organization responsible for phoning voters in the 36th district and mis-representing candidate Paul Rumler's views. The Inside Dope also reports that Personal PAC reports in-kind donations amounting to $27,043.93 to Jacobs' campaign, money spent on a phone campaign telling residents that Jacobs was the only pro-choice candidate in the race. So this phone campaign was a service to the Jacobs campaign and was duly reported as such.
As the Inside Dope points out, we have to assume that Personal Pac made the decision to call voters in the 36th district independently of the Jacobs' campaign because if they did in coordination with it someone would be guilty of a crime. But it seems a strange way for Personal Pac to advance their pro-choice cause. Apparently they see doing favors for pro-choice incumbents as something that will benefit their cause in the long run.
Am I going to apologize for doubting Mike Jacobs' explanation of who made those phone calls. Yes. I apologize for not being cynical enough about Illinois politics to imagine a supposedly pro-choice organization behaving in such a way.