[Zope] External Methods to run ReportLab reports?

I've looked through the mailing lists on zope and reportlab-users and it seems that most people are calling reportlab to generate reports via external methods. Is this the prefered way to generate dynamic reports? And does anyone have some example code I can look at to get started? Ideally I would like to have the ablility to generate dynamic reports as well as cache the most often requested reports. Thanks, Walter