NLog is available as source code and binary packages.
Binary packages are available via NuGet
Binary packages are also available as zip via GitHub
Source code is available at GitHub
Older releases can be downloaded from CodePlex. Installer and zip packages are available.
Support & examples
Tutorials, examples and references can be found on the GitHub wiki
Support (questions, bug reports, feature request) for NLog is available via the GitHub issue list.
Experimental features can be submitted to the NLog Contrib repository, those could be included in the core at a later time.