A quick search for the word "debounce (or de-bounce)" comes up with 21 matches in these forums. You might start there. Doing a simple search helps reduce the problem of generating multiple threads on the same subject.
Below is a simple de-bounce circuit. It uses two cross-coupled NAND gates and a double pole switch. It runs off +5v and it ideal for logic circuits. It should be quite simple and small to construct.