If you want to learn Data Structures in C then at first you should know how the data stores in trees, stack, and array or in queue. Only then one can understand the true mechanism of data structures.
There are very good sites available on net from where you can learn C and Data structure. They can teach you at basic level as well as high level. You have to extract information according to your taste and level Here are some sites where you can learn c and data structures but do practice the codes because practice make man perfect.
For C language go to following sites
' target='_blank' class='qa'>www.learn-programming.za.net
-< a href ="http://www.softlookup.com/tutorial/c++/index.asp" target="_blank" class="qa">www.softlookup.com
- www.theparticle.com/csdata.html ( this one is really good)