How to get information about previous builds from external script?

Hello

  Is there a way to get information (number, date, etc.) about prevous builds (last sucessfull, last pinned, tagged) from external script (e.g. ant). We would like to generate report (e.g. list of fixed defects) for each build so we need possibility to get some "point in time" related to previus build for identifying date range for report (e.g. 01.01.2009 (last pinned build) - 03.01.2009 (today)).

Best regards,
Alexey