Making outs to odds conversion

[smoore]

In holdem, I know that I can take the outs and multiply by 4 on the turn and 2 on the river to get a rough % that I can then turn into odds. How do I figure out the odds of a runner runner situation? I think it's just a matter of memorization for actual use, but I want to know how to figure:

1-two of the same suit
2-two of the same rank
3-two of exact rank (such as for a straight)

2 & 3 may be exactly the same, I don't know.