Business Intelligence and Reporting Tools (BIRT)
BIRT is an open source Eclipse-based reporting system that integrates with your Java/J2EE application to produce compelling reports
Wikipedia page about BIRT
BIRT Help
BIRT Newsgroups: eclipse.birt
HowTo
We now have 3 copies purchased.
Addison Wesley - BIRT A Field Guide to Reporting 2nd Edition - Jul 2008.pdf
Addison Wesley - Integrating and Extending BIRT 2nd Edition - Jul 2008.pdf
Clients
BIRT RCP client appears to be "BIRT light" and has fewer features than the Full version.
MS Windows client "Report Designer Full Eclipse Install" is available at: http://download.eclipse.org/birt/downloads/build.php?build=R-R1-2_2_1_1-200711011610
Linux version is available on this page.