Yangshuo is a great place to learn Chinese. There are a few Chinese schools in Yangshuo. Omeida Chinese Academy being the most prominent. I have had the great fortune to have a few lessons at Omeida and I found it very good. The staff are friendly and will be glad to help you with anything you need.
Most students seem to get 1-on-1 lessons or maybe 2-to-1 which is great because you get so much individual attention. Omeida is a nice place to drop in and have a chat with the staff or even visit there canteen. Meals are 9rmb and this means unlimited rice and you share five different dishes at a communal table. If you are learning Chinese this is wonderful as you can sit at a different table each day and meet so many different people and learn alot of Chinese. Courses include accommodation and meals and the school also owns an English school so its easy to find a language partner and a bunch of friends.