The Apache Aries incubator project is aimed at delivering an implementation of the EEG specifications that are part of the enterprise OSGi programming model. It sets out to provide enterprise OSGi componentry that can be integrated into application or integration server runtimes - such as Geronimo and ServiceMix - without being tied to any one of these.
Read Ian Robinson's post entitled 'OSGi in the Enterprise – the Apache Aries incubator'
The Aries project is delivering a set of pluggable Java components enabling an enterprise OSGi application programming model. This includes implementations and extensions of application-focused specifications defined by the OSGi Alliance Enterprise Expert Group (EEG) and an assembly format for multi-bundle applications, for deployment to a variety of OSGi based runtimes.
The OSGi R4 V4.2 Enterprise Specification can be found here:
To understand the complete scope of the Aries project, see the Aries proposal document on the incubator wiki.