Carp on the fly has got to be one of my favorite kinds of fishing, if not my favorite. I have only been doing it for a year now, but it has so vastly improved all aspects of my fishing it's unbelievable. If you have a little patience you will catch them, and it is an absolute blast when you do. I'll give some basic pointers and then at the end I'll provide a list of some great carp fly fishing blogs.
Gear: Wear high quality polarized sunglasses and a brimmed hat. I use Costa 580 lenses, and they are spectacular. But any pair of quality polarized sunglasses will work, and are a must. I have two carp outfits. I have a 7'6" 5 wt I use for smaller creeks, and the smaller carp that live in them. For a while this was my only carp setup, and it worked fine. Until one day I hooked up with a real bruiser, and the rod and reel really were no match. I landed the fish, but only with some patience and luck. Hook something like that near any kind of brush and you can kiss it goodbye. Like I said, the 5 wt IS great for fishing small, clear spring creeks and making super delicate presentations. The average creek carp with run you into your backing on a 5 wt. I use just a standard weight forward 5 wt line of a muted color. For many trips I used bright orange with about 11 feet of leader and tippet, and the carp never seemed spooked, so you can probably get away with whatever color you have. I use a leader of 8 lb and a fluorocarbon tippet of 8 lb as well. The particular model rod is a Dogwood Canyon (Bass Pro Special), and the reel I use is a Cabela's Prestige Premier. They both function flawlessly for what I use them for. My big carp setup is a 9' 7wt. I use this for the waters with lots of brush and/or big carp. It is overpowered for small creeks, but it is still a great fight on the bigger carp. In the beginning I was all for light tackle, but now I have realized the 7 weights are definitely a better choice when you are dealing with lots of snags or big carp, or both. And a nice carp will still run you well into the backing on a 7 wt. Again, I use dull colored, weight forward line, and a 9 foot 8 lb leader with a 8 lb tippet. The rod I use is an Echo Ion, and the Reel is a Cabela's RLS. They are both great.
Flies: In small creeks, I like to use medium to large, mud colored nymphs. Small, lightly weighted crayfish patterns also work great (Carp candy, Whitlocks Near 'nuff size 8). When I fish the bigger waters, I use almost all crayfish patterns. Whitlock's Near 'Nuff is always good to me. I like a size 6 in deeper water, and a size 8 for shallow water when the carp could spook easily. Carp Candy and Stalcup's Crazy Dad work great as well.
There are a few things carp will do that call for somewhat specialized flies. Some days, carp will squirm into the shallowest waters, backs out of water, feeding aggressively. My go to fly is a San Juan Worm. It lands delicately, but is nice and bright and attracts their attention. A well placed fly all but guarantees a hook up. Another strange thing carp will do it shove their faces into the bank and root ferociously, I assume for insects. This is when I pull out either a small black or brown Wooly Bugger, or a Red San Juan Worm. I prefer the Wooly Bugger, as I feel a SMALL, SMALL, SMALL disturbance upon entry into the water can be beneficial in this case. Again, a well placed cast is an almost certain hookup.
There are times when carp eat at the surface, but I have never successfully caught one as I have only seen them doing it a handful of times.
Presentation: I can't stress enough how spook carp are. Sneakiness is a virtue when carp fishing. I wear muted colors. Usually longs sleeved pants and shirt to protect from the burn hazel as I stalk the banks. Look for puffs of mud, tails wagging in the shallows, bubbles, or simply the carp itself. When a carp is spotted, crouch down slowly and think of a game plan. Make as little movement as possible. If you spook a carp, you spook the whole school as carp emit pheromones warning other carp nearby of danger. Cast a few feet beyond the carp and bring it in to him. I like the flies around six inched left or right of his nose. That way he sees it, and you see him turn and take it. When a carp bites, there is no feel transmitted to your hand. You have to watch him and either see when he takes it or guess. Usually as soon as he takes the fly, he spits it right back out, realizing it is fake. So you have to be quick on the draw, but not too quick. Carp also have incredible smell/taste. Rub your fly in the mud to cover up your scent on it. After a little time on the water, you will begin to recognize the body language of carp that are not interested in eating. I usually seek out the carp that are actively feeding by stalking from the banks. I have fished for many kinds of fish, from bass to tuna, and carp are by far the hardest to fool. So if you find yourself spooking a lot, don't be discouraged. There is so much more to learn, and I am sure you will have a blast catching your first carp.
Here are some links:
http://carponthefly.blogspot.com/
http://www.flycarpin.com/
http://thirdcoastfly.com/category/carp/
http://goldenbonefish.com/
http://www.youtube.com/watch?v=WevZGgZYTPc&feature=related
