If you are interested in a bit of a tutorial on various Chinese teas, you can find quite a bit of information on my site.  The tea education information is located in the drop-down menus at the top of the home page.  
While I specialize in pu-erh teas, I carry a rather nice selection of white, green, oolong, and black teas.  I don't have any yellow tea yet but have identified a source in China and will probably have some on the site soon.  Pu-erh teas are my favorites but next to that the Taiwanese Oolongs teas are the teas that I tend to go to for variety.  
Let me know if you have any questions.
Best regards,
Steve
www.JAS-eTea.com
sales@JAS-eTea.com