Well flyfishing takes a lot more skill than bait fishing. Think of flyfishing as stalking and hunting and baitfishing as trapping. Basically you are trying to fool a fish into thinking that litle bit of fluff with a hook in it is an insect or a small fish. Not as easy as it sounds, but when you have caught one, the wait will have been worth it! I fly fish in the sea as I'm an akward sod and don't believe in making life easy. Like most saltie fluff chuckers, I have more blanks than catches, but it's soo much better when I do catch. I got into it as I was fed up of carrying all the kit for baitfishing. Fluffing is so much more minimalist, but it costs more as it is still considered a gentlemen's sport, and they can afford it. Grr... My fly rod is worth £450, but i got it as a pre production prototype for next to nothing. The greys missionary is quite a good rod, so if you are happy with it, then go for it. The numbers refer to the rod and line weight, which should match. ie if the rod is a 7 weight (#7) then the line should be too, or the line could be one heavier, say an #8. Then you have the type of line, floating, sinking, intermediate etc, and the taper, either weight forward (the end you cast with is thicker and heavier) or double taper where the weight is in the middle. I would say for a novice try a weight forward floater. To this you tie a leader which is normally tapered. For sea or carp I use a 7ft leader of 20lb then tie a 10lb tippet on that which the fly is tied to. If you are after trout then I have no idea as I don't do that, but a lot lighter lines I would have thought. Are you near the sea? If so have you thought of sea fluffing? Have a look here if you are:
http://www.ukswff.co.uk/index.htm
Also see here:
http://www.fishandfly.co.uk/sal****er.html (BUT THE SWEAR FILTER WON'T ALLOW THE LINK BECAUSE IT SAYS 'SAL****ER' SO COPY AND PASTE THEN ENTER 'SALT' AND 'WATER' AS ONE WORD. where the stars are. Grr etc...)
If you go to their homepage there should be info on regular fly fishing too.
Most important thing is to get some casting lessons straight away. This is most important or you'll start with some awful bad habits. As someone said, keep the wrist straight. It is a good idea to tuck the butt of the rod into your sleeve cuff to stop it moving. The trick to casting is the flick. If you can do this at the right time you will cast with minimal effort. The flick is best described as when you flick paint off a brush. The sudden stop is what sends the fly line out. One way to practice is to get the butt section of the rod and hold it the wrong way up, so that the butt is in the air. Now flick it as you would cast and stop suddenly. The reel seat clamp should flick up and strike the tightening ring. Now practice doing this back and forth from 10 til 2, keeping the arm bolt upright, and not moving the elbow. Eventually, as you leatn to cast and get more line out you will also push the forearm back and forth a bit too, but let's not go there yet. The main thing is keep the wrist locked and keep the arm stright up, don't bend to either side. See here for the best casting resource on the net, written I think, by the guy who taught me (Berlin on the UKSWFF forum who is somewhere up your way)
http://www.sexyloops.com/flycasting/contents.shtml
Good luck and tight loops!!