Cacti is a complete frontend to RRDTool. It stores all of the necessary information to create graphs and populate them with data in a MySQL database. The frontend is completely PHP driven. Along with being able to maintain graphs, data sources, and round robin archives in a database, Cacti also handles the data gathering. There is SNMP support for those used to creating traffic graphs with MRTG.
Information regarding Project Releases and Project Resources. Note that the information here is a quote from Freecode.com page, and the downloads themselves may not be hosted on OSDN.