C language is used for creating computer applications and also used a lot in writing embedded software/firmware for various electronics, industrial and communications products which use micro-controllers.
It is also used in developing verification software, test code, simulators etc. for various applications and hardware products.
If you want to learn C programming then you can try out these resources
You can go to your local library or store or an online store like Amazon.com to find many books, DVDs, and etc. for learning many things
C All-in-One Desk Reference for Dummies is a good introductory book for learning C Programming
http://www.amazon.com/All-One-Desk-Reference-Dummies/dp/0764570692/ref=cm_cr_pr_product_top#_
You can use a search engine like Google.com to find free tutorials, ebooks, forums, videos and other information
There are many online forums for C programming and etc...whenever you need advice or information for these programming languages then you should go to one of these forums because they are experts in C programming and they can really be helpful
C forum
http://www.google.com/search?hl=en&source=hp&q=C++++forum&aq=f&aqi=g9g-s1&aql=&oq=
The website HowStuffWorks has good tutorials for C programming, Java, and etc.
C Programming
http://www.howstuffworks.com/c.htm
Free C programming course
http://www.google.com/search?hl=en&q=Free+C+programming+course&oq=Free+C+programming+course&aq=f&aqi=g2g-v2&aql=&gs_sm=12&gs_upl=37360l37360l0l38469l1l1l0l0l0l0l62l62l1l1l0&gs_l=serp.12..0l2j0i15l2.37360l37360l0l38469l1l1l0l0l0l0l62l62l1l1l0.frgbld.
C tutorial
http://www.google.com/search?hl=en&source=hp&q=C+tutorial&aq=f&aqi=g10&aql=&oq=
Cprogramming.com and Cprogramminglanguage.net have many good tutorials, programming tools, online forum, and etc. for learning C and C++ programming
http://www.cprogramming.com/tutorial.html
http://cprogramminglanguage.net/
YouTube has videos for learning almost any subject or topic
C Programming
http://www.youtube.com/view_play_list?p=78280D6BE6F05D34&search_query=C+programming
C Programming, playlist
http://www.youtube.com/results?search_query=C+Programming%2C+playlist&oq=C+Programming%2C+playlist&aq=f&aqi=g1&aql=&gs_sm=12&gs_upl=149921l149921l0l151015l1l1l0l0l0l0l94l94l1l1l0
Good luck and I hope this will help