There are Wifi Service in some coffee houses and some restaurants like Jono Chinese-Western Restaurant. Starbucks will open their branch in Changsha in this National Day's Holiday, I think it would provide free Wi-Fi service for its customers as it has done in other cities. The new Starbucks is located at Wangfujing Shopping Mall.

There is free wireless internet in the Starbucks. Rather slow and
unreliable, but the price is right. The entire area around
the Wangfujing Department Store is under 24hr construction, so
it might be a bit hard to find for the next little while.