Introductory text for calculus of variations I am currently working on problems that require familiarity with calculus of variations. I am fairly new to this field. Please suggest a good introductory book for the same that could help me pick up the concepts quickly.
edit:
I would prefer books which are available in PDF format online.  

If you check out Wikipedia's entry on "Calculus of Variations: here, and scroll down to the bottom where "References" are listed:


*

*You'll find a link to a pdf reference (Jon Fischer, Introduction to the Calculus of Variation, a quick and readable guide) that might be exactly what you're looking for, as well as some additional references (sample problems, guides, etc.).  

*In addition, you'll find a link to this site listed among the references.

*There's also a chapter of a text that's available online: Chapter 8: Calculus of Variation from Optimization for Engineering Systems, by Ralph W. Pike.
There are also some additional texts and resources listed in the linked Wikipedia's entry, as well.
