earning a draw

what are the rules concerning forcing a draw through repeatedly checking your opponent? I was told that it can be done after a certain amount of moves have been made. Is this correct?

Yes, that tactic is called Perpetual Check...

ADK

There are basically  4 types of draw according to FIDE rules:
1. Stalemate- If the player on turn has no legal move but is not in check, this is stalemate and the game is a draw. 

2. Mutual agreement- A player may offer a draw to his opponent at any stage of a game. If the opponent accepts, the game is a draw. 

3. Threefold repetition- If an identical position has occurred three times, or will occur after the player on turn makes his move, the player on move may claim a draw. In such a case the draw is not automatic - a player must claim it. 

4. Fifty move rule - If at least fifty moves (by each side) have passed with no pawn being moved and no capture being made, a draw may be claimed by either player. Here again, the draw is not automatic and rather must be claimed. 

Other types of draw:
1. Impossibility of checkmate - if a position arises in which neither player could possibly give checkmate by a series of legal moves, the game is a draw. This is usually because there is insufficient material left. Combinations with insufficient material to checkmate are: 
a. King versus king 
b. King and bishop versus king 
c. King and knight versus king 
d. King and bishop versus king and bishop with the bishops on the same color. 

2. Perpetual check— Where one player gives a series of checks from which the other player cannot escape—is a draw, but in fact there is no specific provision for this in the laws of chess. However, any perpetual check situation will eventually be claimable as a draw either under the fifty move rule or by threefold repetition. In perpetual check situations, a draw by agreement is likely.

http://en.allexperts.com/q/Chess-1332/Draw.htm

cheers!