LibNZBGET is an NZB retrieval library, based on the NZBGet newgroup client.
The library is written in C++, and focuses on ease of use.
Most features are copied from NZBGet and should work well out of the box.
The class documentation can be found here.
An example can be found here libnzbget-example.tar.gz
The project sources can be acquired from svn.
Install LibNZBget for Ubuntu Natty Narwhal by adding ppa:ranzbak/libnzbget
Mail me at: paul <at> printf.nl