Full documentation for the Ethereum Name Service can be found as EIP 137. This package offers a simple binding that streamlines the registration arbitrary utf8 domain names to swarm content hashes.
The SOL file in contract subdirectory implements the ENS root registry, a simple first-in-first-served registrar for the root namespace, and a simple resolver contract; they're used in tests, and can be used to deploy these contracts for your own purposes.
The solidity source code can be found at github.com/arachnid/ens/.
The go bindings for ENS contracts are generated using abigen via the go generator:
go generate ./contracts/ens