Planning Center Online allows to create custom reports (i.e. print templates) for plans: http://help.planningcenteronline.com/s/planning-center/m/planning-center/l/49253-custom-reports-wiki
To create reports with landscape orientation it is import that style tags have no type attribute. Otherwise the generated PDF files are always (independent of selected print options) in portrait orientation with large margins.
This is probably due to a bug in the used PDF generator (“Prince”, currently used version is 7.1).