I want to start this off and I'm hoping others will add to this. I don't know if a good FAQ exists on the net anywhere.
The scale.I think its safe to say that most of us model in 1/87 or HO scale. This is the most popular model railroading scale right now and has the most kits and other parts available. You can model in other scales but will be mostly limited to scratchbuilding everything.
Research. There is a ton of information to be had right here in this forum. Also, Matt has a page set up here
www.carnivalwarehouse.com/models/models.asp There is also the ridemodelers group at groups.yahoo.com/groups/ridemodelers
Get lots of pictures. Pictures are the most valuable resource in modeling anything. Most of my carnival pics are taken with modeling in mind. I really don't need a shot of every Octopus I come across but I do need detail shots of different angles. I also "borrow" a bunch of pics from other online photo albums. Chris Hurley's albums are a valuable resource.
MaterialsModels can really be made from anything you can get your hands on. Most of us that scratchbuild prefer working with styrene plastic. Its easy to work and glue. It holds paint well and comes in a ton of different shapes and sizes. Evergreen and Plastruct are the two big manufacturers.
www.evergreenscalemodels.com www.plastruct.com Peripheral equipment like trucks and trailers can be had from Boley, Herpa, Promotex and Walthers. There are a ton of truck manufacturers out there that produce one or two models in cast metal or resin.
www.dept187.com www.herpa.de www.promotex.ca www.walthers.com www.1-87vehicles.org is a good place to start for truck modeling.
www.truckstopmodels.com is a good place to buy from. Remember that they rides have to move down the road somehow.
Ebay.What more can I say? This is _*THE*_ place to find out of production models. New models can also be had. Make sure you don't get price gouged though. If you set up some searches and check in often you can get most of your models here. This includes the trucks and trailers as well.
Ride manufacturers (current)
Faller. German company that makes rides in 1/87 scale from injection molded plastic. This is the best going in kit form. They are even operational if a little finicky. They are European prototypes so the rides are big and flashy.
www.faller.de International Hobby Corp (IHC). US company that makes plastic injection molded ride kits. They are of dubious quality and some are even knock offs of Cummons rides. They can be good for starters and kitbashing. Most will operate.
www.ihc-hobby.com Reynaulds Midway Miniatures. Warren builds mostly in 1/87 scale but will build some rides in other scales. These are not kit form. Great quality but not motorized. I think you could get them to work with some tinkering.
www.rmmridemodels.com RAH Models. Kit models from vacuum formed plastic and cast plastic. They require some work but can turn out pretty good. Non-motorized but with some tinkering could get to work.
www.rahmodels.com Amusement Graffix International. Mostly scenery packs to change the Faller models to be more Americanized. I think they are going to offer a ride or two in the future but nothing firm.
www.amusementgraffixintl.com Cummons Scale Amusements. Prebuilt rides. Fully operational. Made mostly from cast metals. Pewter I think. Really good quality and highly sought after. webpages.charter.net/csai
Other modelers. There are some modelers that will build rides. This is not a steady resource but could provide a unique ride or two.
Food and Game ManufacturersFaller makes some euro style games. They aren't really suitable for modeling US midways though. Same with their food trailers.
International Hobby Corp has some kits that are closer to US prototypes but may be out of production now.
RAH Models makes a few stick joints and some food trailers.
Ridemodelers group on Yahoo. Downloadable paper models. Print, cut, fold and glue. They are based on US prototypes.
Raymond