Hi all !
This information is truly very helpful.

Steve said ....
"The REALLY good interviewers can ask several easy questions and figure out your body language to determine when you are remembering something and when you are making something up (or lying). But, most interviewers aren't REALLY good!"

I would like to add to it....

When a person is asked some question and if his eye balls move up(i.e. they point upwards) the person is trying to remember and if he looks down ward ..(i.e. eye pointing downward) the person is trying to Imagine or making something up.

But if interviewers asks a question, which I have no experience on ..but know a bit or theoretically know some thing. would it be good to say ..that "I don't know, but I guess It should be this way or I'll do it this way" and give some explanation to it.

Well, I faced some similar situations and said this way, I don't know if the interviewers liked it.
What should be a good response ?
Regards
Vignesh baliga