For more detailed information on the concepts and philosophy behind aspect orientation, check out the following web sites:
The official information on the AspectJ project at Xerox PARC.
The official AspectJ development technologies download site with links to support tools.
Eclipse has a set of AspectJ Development Tools collected as a downloadable feature using the built-in update site mechanism from the listed web site.
A plug-in for Borland JBuilder that allows integration with AspectJ is available at this site.
A plug-in for NetBeans to support AspectJ development is available from this web site.