PGFplots is a TeX packages for creating plots. It is build on top of build on top of PGF and allows you to create sophisticated plots in a rather intuitive and easy manner.
Disclaimer: This site is not the official home of PGFPlots. Consult the Sourceforge project page for releases, support and bug reports.
Track the development of PGFplots.
German site which also offers support for PGFPlots.
Subforum for Graphics including PGFplots on LaTeX-Community.org
PGFplots topic list in the LaTeX-Community.org forum.
For questions about pgfplots features, bug reports and developer communication.