I read few articles on web to find out how Agile, XP, Scrum, pair programming are different from each other / related to each other and I derived the following line:


Scrum and XP are almost same. XP has shorter period of releases than Scrum
Pair programming is employed in both Agile and XP methodologies


But I was unable to identify how Agile is different from XP.

More than providing a URL, I would be happy to read your experience and thoughts on this.

You are confusing the issue. Being agile means that you are following a bunch of values and practices from the agile manifesto. Thats it. 

XP and Scrum are development processes that follows those values. Both are "just as agile". The big difference between Scrum and XP is that Scrum does not contain practices specifically for programming, whereas XP has lots of them (TDD, continuous integration, pair programming). 
