With the release of Eclipse Juno, BIRT 4.2 is now available and features a new Excel data source that can consume multi-sheet XLS or XLSX files. BIRT now delivers a POJO or OSGi based runtime for deployment of the BIRT Viewer and Report Engine. In addition BIRT now features a build process change that will make the BIRT runtime artifacts available to Maven users, a new Donut chart type, custom cache control on data sets, and better aggregation support that allows filtered rows to be included in aggregated data. BIRT also adds support for building derived cube measures, relative time period calculations and relative file path support for most data sources and connection profiles. To read more about the new features have a look at the BIRT 4.2 New and Notable.BIRT 4.2
If you are interested in contributing to the BIRT project, see the BIRT Community page.