We enjoy booking our domestic China flights on eLong and it is easy and fast. We just booked our parents flights from Nanjing to Beijing and it was less than the bullet train. Elong is part of the Expedia Company but I think the elong booking process is a lot more efficient. If you are looking for domestic flights in China I would definitely check out their website, www.elong.net . It displays its information in English and Chinese. Also definitely sign up with an account because a lot of travel sites will give rewards and hotel discounts or free.
Passionate for everything related to China travel.