Online data collection within social and behavioral research is burgeoning. For surveying individuals online, researchers are increasingly relying on online panels and similar subject pools. phpPanelAdmin is a Web-based platform that is intended to assist researchers in quickly setting up and managing an online panel. phpPanelAdmin solves many problems that can arise when one is collecting data in online panels. As an open-source program placed under GNU General Public License, phpPanelAdmin (www.goeritz.net/panelware) is not only free of charge but free of restrictions on its use, modification, and distribution. Building a new online panel-which before required weeks and special skills-is now possible within minutes and at no cost. Furthermore, phpPanelAdmin can be connected to an existing online panel or even be used for managing offline subject pools. Functions include creating a panel sign-up form; automatically unfolding the panel database; searching for panelists; viewing, modifying, and deleting panelists' data; deleting and cloning variables; drawing samples; sending e-mail to panelists; exporting data; displaying panel statistics at a glance; identifying duplicates; creating and managing e-mail templates; executing user-defined SQL statements; and obtaining help.