According to that link there is now a BTG wallet available:
http://btgolds.org/However, it asks for your private key so I'm highly suspicious.
Anytime something asks for your private key, you should be suspicious. But the only way to claim Bitcoin Gold is by your Bitcoin private key. It is highly recommended you move your Bitcoin away from that private key before using it claim BitCoin Gold. If it is a scam wallet, they will steal both your BTG and your BTC. Be careful.
Edit, from the post above, it looks like this might be a Scam wallet. I'd avoid it until there is a community vetted open source wallet available.