Look up PGN online...
http://en.wikipedia.org/wiki/Portable_Game_Notation
http://www6.chessclub.com/help/PGN-spec
It's easy, almost the same way you'd write the moves down for yourself in algebraic notation, other than comments go inside the {...}, and the tag format at the beginning for listing the names etc. is in a special format with reserved words inside square brackets [...], checkmate is "#", etc. PGN still works even if you list your moves with one move per line instead of in a row. Then when you go to post your game, click on the little brown-and-white checkerboard to upload your PGN file, which is just a text file with a ".pgn" extension.
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EXAMPLES
(1)
[Event "F/S Return Match"]
[Site "Belgrade, Serbia Yugoslavia|JUG"]
[Date "1992.11.04"]
[Round "29"]
[White "Fischer, Robert J."]
[Black "Spassky, Boris V."]
[Result "1/2-1/2"]
1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 {This opening is called the Ruy Lopez.}
4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 d6 8. c3 O-O 9. h3 Nb8 10. d4 Nbd7
11. c4 c6 12. cxb5 axb5 13. Nc3 Bb7 14. Bg5 b4 15. Nb1 h6 16. Bh4 c5 17. dxe5
Nxe4 18. Bxe7 Qxe7 19. exd6 Qf6 20. Nbd2 Nxd6 21. Nc4 Nxc4 22. Bxc4 Nb6
23. Ne5 Rae8 24. Bxf7+ Rxf7 25. Nxf7 Rxe1+ 26. Qxe1 Kxf7 27. Qe3 Qg5 28. Qxg5
hxg5 29. b3 Ke6 30. a3 Kd6 31. axb4 cxb4 32. Ra5 Nd5 33. f3 Bc8 34. Kf2 Bf5
35. Ra7 g6 36. Ra6+ Kc5 37. Ke1 Nf4 38. g3 Nxh3 39. Kd2 Kb5 40. Rd6 Kc5 41. Ra6
Nf2 42. g4 Bd3 43. Re6 1/2-1/2
(2)
[Event "State Ch."]
[Site "New York, USA"]
[Date "1910.??.??"]
[Round "?"]
[White "Capablanca"]
[Black "Jaffe"]
[Result "1-0"]
[ECO "D46"]
[Opening "Queen's Gambit Dec."]
[Annotator "Reinfeld, Fred"]
[WhiteTitle "GM"]
[WhiteCountry "Cuba"]
[BlackCountry "United States"]
1. d4 d5 2. Nf3 Nf6 3. e3 c6 4. c4 e6 5. Nc3 Nbd7 6. Bd3 Bd6
7. O-O O-O 8. e4 dxe4 9. Nxe4 Nxe4 10. Bxe4 Nf6 11. Bc2 h6
12. b3 b6 13. Bb2 Bb7 14. Qd3 g6 15. Rae1 Nh5 16. Bc1 Kg7
17. Rxe6 Nf6 18. Ne5 c5 19. Bxh6+ Kxh6 20. Nxf7+ 1-0
Could somebody please tell me how i can post a game in a comment or post (like, the interactive, live board where you can scroll through all of the moves), that'd be great!