Can anyone tell me what is this PGN?? i see it for each and every game !!! is der any special significance abt it ??? wats the use of downloading it ???

It's just the bare-bones basic file of the game.  If you download it, you replay the game with almost any program, and/or save it to your database.

It's also the smallest version of a game file to save, or to email to someone else.

How to read that PGn file ??

When I'm offline, I prefer BabasChess:

http://www.babaschess.net/

It's free, free of malware and customizable to your preferences as to color etc.

If you were asking about a program to read the PGN format then the last reply contained a link for a popular program (also chessbase light is another popular one)

http://www.chessbase.com/download/cblight/index.asp

but if you want to know more about the PGN format, you better see this link

http://en.wikipedia.org/wiki/Portable_Game_Notation

Yeah thx...Im clear