[Suneet]

Well, the details really don't matter if you don't have some background. String theory is an outgrowth of the long quest in physics to unify the forces of nature (and as you should know, there are four of them). Unifying forces means to write down a single model that describes two or more forces, thus showing that forces which we thought were different from one another are actually parts of a single, unified force. For example, the force of Electromagnetism and the Weak Force are unified in Electroweak Theory, which was written down in the 1960s (I think). So the deal is that we can unify three of the forces : E.M., Weak, and Strong Forces. But unifying Gravitaion in to this structure is difficult. String theory is an attempt to do that. So far, we don't have enough of the theory to make any experimental tests.

For more, I suggest "The Universe in a Nutshell" By Hawking and "The Elegant Universe" By B. Greene

My math prof. last semester specialized in Topology, so now he's a string theorist. He'd drop comments and such in class all the time, but I've not quite progressed to unified field theories yet...