Good for you...I think rugby is the greatest sport and love watching it (Go ALL BLACKS!!!)! There are A LOT of rules from the IRB...here is a brief list for you...then some sites where you can get more detailed info.
1. As you notice, there are no shoulder pads or crash helmets in rugby.
2. The ball must be pitched backwards to your teammates. No Forward passes like John Elway.
A team can pitch the ball back and forth to each other as many times as they wish.
3. THERE IS NO BLOCKING to assist your runner.
4. Everyone runs with the ball and tackles equally. Unlike American Grid-Iron Football where 2 or 3 guys get all the glory and the rest of the team is never given the opportunity to prove themselves and run for a score, every player on the rugby field will run with the ball and tackle over 20 times a game. If you were an offensive lineman and never ran the ball and never tackled this game is for you! Everyone will be a running back and linebacker. When a set dead-ball scrum is formed, that is when the team will get in their SET POSITIONS, but shortly after that when mass chaos breaks out, all players will run and tackle with the ball.
5. When you are tackled you have 1 second to let go of the ball and purposely “fumble” the ball. Don’t touch it again until you are up from the pile and standing on your two feet again.
6. When you TACKLE someone, you can’t pick up the fumbled ball until you are ON YOUR FEET. This is one of the most called penalties on new players. You must be standing up to pick up the ball. You cannot dive on a loose ball.
7. When you are on defense, and a tackled player is put to the ground, you must make sure you are on YOUR SIDE OF THE “scrumage line” BEFORE you engage in any physical contact with the other team. This is called offside and is one of the most called penalties for all levels of players. This happens when a defensive player is chasing down a runner from behind. The defensive player must run around the ruck pile and enter from the other side to give contact on the ruck pile. This is a very big yardage penalty if you get caught not being on sides on a loose ruck pile.
8. The game will have 15 players from each team taking the field
9. When you teammate pitches the ball to you as you are running down the field, and you accidentally drop the ball. THAT IS A PENALTY, it is called a “Knock On”. The other team will get the ball automatically right there for their possession. As you can see, this is the kiss of death when you drop or “Knock On” the ball deep in your own territory by their scoring end zone. This is why we run so many ball-handling drills in practice, to cut down on these penalties.
10. There are no “Downs” in rugby like football. An offensive team may have the ball for 20 “phases” or “downs” in a row, if they can keep winning the ruck pile and push over the tackled player to win the ball and regain possession. It is very important to always be in “support” and chasing after your ball carrier at all times. When your offensive player is tackled and there is 4 offensive players running right behind the ball carrier, they should no doubt be able to push over the 2 or 3 defensive players that are at the tackle area or the “ruck pile”. On the other side of the coin, if no offensive players are in support and the ball carrier is tackled, the defense will simply just step over the ball and the ball carrier, to pick up the loose ball. The offensive player must “REALEASE” the ball in 1 second. The Defensive team will just pick it up and run the other way if no offensive support is right there. It is VERY IMPORTANT TO BE IN SUPPORT AND HAVE 4 PLAYERS RIGHT BEHIND A BALL CARRIER. (1)You will be there for a pitch-pass. (2) You are there for a ruck over to win the ball.
http://www.scrum.com/rugby_guide/
http://www.irb.com/Laws/
http://wildcat.wsc.edu/clubs/rugby/rules/
http://news.bbc.co.uk/sportacademy/bsp/hi/rugby_union/rules/basics/html/default.stm