Rugby’s point-scoring system is very similar to American football:
Try (Touchdown) = 5 points
Conversion (Extra Point) = 2 points
Penalty Goal = 3 points
The most basic rule of rugby states that all passes must be made backwards (ie no forward passing as in American football). This rule is the foundation of the sport known as rugby and all other rules stem from that single rule.
Download the International Rugby Board’s 2009 Laws of the game here.
Also, make sure to check out the IRB Laws of the Game flash website. This site has tons of flash videos outlining the rules and equipment etc.