And how do you start a game in the first place? (so far the only games I've played are in 960 tournaments set up by someone else).

Thanks.

A. Technophobe. 

Check Wikipedia:  http://en.wikipedia.org/wiki/Chess960#Rules_for_castling

Fischer Random Chess allows each player to castle once per game, moving both the king and a rook in a single move. However, a few reinterpretations of standard chess rules are needed for castling, because the standard rules presume initial locations of the rook and king that often do not apply in Fischer Random Chess games.

After castling, the rook and king's final positions are exactly the same as they would be in standard chess. Thus, after a-side castling (also called sometimes c-castling) the king is on c-file (c1 for White and c8 for Black) and the a-side Rook is on d-file (d1 for White and d8 for Black). This castling notated as O-O-O queen-side castling in orthodox chess. After h-side castling (also called sometimes g-castling) the King is on g-file and the h-side Rook is on f-file. This move notated as O-O and known as king-side castling in orthodox chess. It is recommended that a player state "I am about to castle" before castling, to eliminate potential misunderstanding.

However, castling may only occur under the following conditions. The first two are identical to the standard chess castling rules. The third is an extension of the standard chess rule, which requires only that the squares between the king and castling rook must be vacant.

1. Unmoved: The king and the castling rook must not have moved before in the game, including castling.
2. Unattacked: No square between the king's initial and final squares (including the initial and final squares) may be under attack by any opposing piece.
3. Unimpeded: All the squares between the king's initial and final squares (including the final square), and all of the squares between the rook's initial and final squares (including the final square), must be vacant except for the king and castling rook. An equivalent way of stating this is that the smallest back rank interval containing the king, the castling rook, and their destination squares contains no pieces other than the king and castling rook.

If the initial position happens to be the standard chess initial position, these castling rules have exactly the same effect as the standard chess castling rules. In some starting positions, some squares can stay filled during castling that would have to be vacant in standard chess. For example, after a-side castling (O-O-O), it's possible to have a, b, and/or e still filled, and after h-side castling (O-O), it's possible to have e and/or h filled. In some starting positions, the king or rook (but not both) do not move during castling.

My Home>Online Chess>Start New Game>Show More Advanced Options>Game Type=Chess960.

Thanks for the help. It's a fun game.

thanks for the caste info!! Actually played first round not knowing!!

how to castle king?

You need space either side. The pieces then go to the squares they would have normally. Try it out on the analysis board as you go.