The home page of Bitcoin Gold is http://btcgpu.org.
As a hard fork Bitcoin Gold aims at releasing an improved Bitcoin protocol.
Quoting Coindesk's First Cash, Now Gold? Another Bitcoin Hard Fork Is on the Way:
Bitcoin Gold wants to create a truly decentralized bitcoin by opening up mining to more participants by replacing bitcoin's mining algorithm with one that will enable it to be mined with graphics cards.
Bitcoin gold will implement a proof-of-work change from bitcoin's SHA256 to Equihash, a memory-hard algorithm that is ASIC-resistant and optimized for GPU mining.
Application Specific Integrated Circuit (ASIC) chips is the hardware that is used to do the mining. They are manufactured primarily in China by basically one manufacturer and this creates an incentive for that company to use its monopolistic market position to ramp up the prices. (see Will 25 October be the D(isaster)-Day for Bitcoin holders?)
This means that mining can be done on other machines so that we truly can aim at a globally distributed ledger (blockchain) and not the centralized version that we have now when the ledger is hosted in a few geographic locations (see Will 25 October be the D(isaster)-Day for Bitcoin holders?)
GPU mining can't prevent centralization. GPU [markets] are controlled by Nvidia and AMD
every bitcoin user at the time will have an equal amount of bitcoin gold associated with their private key.
It is a minimalist fork of the Bitcoin Core codebase in the spirit of litecoin – only a few conservative modifications