Here are two posts from Amy on the binder method....

Coupon Organizing:
I know most of you organize your coupons by three hole punching the entire packet or using a plastic box method. However, I have found what I believe is a simpler way to organize coupons.
You will need a zippered 3 ring binder, some clear baseball card holders (you can find these at dollar stores, Target, Walmart etc...) and one clear 3 pocket Photo Holder page per grocery store (found at the craft store.) At the front of my binder I label a clear photo page holder with each grocery store name. These pockets can be used for rainchecks, in store coupons and shopping lists. I then label the baseball card pages by category.
My categories are:
Baby
Bread and cereal
Cleaners
Dairy
Dessert
Meat
Medicine
Paper Goods
Personal Hygiene
Miscellaneous.
You can use any categories you want and even sub categorize (ie.. I have 6 card pages for my Bread and Cereal catergory: Cereal, breakfast foods, bread, pasta, rice, crackers/chips). I then insert cut coupons in each baseball card slot in its' specific category (You can separate all coupons individually or, for example, put all women's deodorants in one slot).
It is so easy to read each coupon and its' expiration date. Instead of shuffling through pages or piles of coupons you turn to the catergory you are looking for and immediately you can find the coupon. No more exhaustive hunting. It is also easier to purge expired coupons once a month because the expiration date is clearly visable. This method does take time initially because you have to cut each coupon, but finding them when you need them saves time overall.
Another tip is to insert one baseball card holder page after each grocery store labeled photo page. You then insert all the coupons you will be using for each store. You can then flip your binder open in the cart seat and have everything at your fingertips. And if you see a good deal while shopping you can find a needed coupon in seconds. Also, use the slot at the back of your binder to store sale ads. I have done this for about 11 years and love it.

For those of you who need it, here is my binder recipe:
2" Zippered Binder w/Strap!!!
STORE SECTION: Your Favorite Stores (3-pocket Photo holders for rainchecks, Shopping List & Store coupons with a Sticker Tab Attached and Store name inserted followed by one 9-slot Basball card page so you can organize the coupons for the store for the week.
CATEGORY SECTION: 10 Categories (Tab dividers labeled on both sides & 9-slot Baseball card holders-sometimes called trading card pages!)
Baby - 2 baseball card pages (Diapers/Shampoos, Baby Food)
Bread & Cereal - 5 baseball card pages (Cereal, Breakfast Foods, Breads, Rice/Pasta, Chips & Crackers)
Cleaners - 8 Baseball card pages (Floor Cleaners, Dish Cleaners, 2 Fabrics, Standard Cleaners, Bathroom Cleaners, 2 Air Fresheners)
Dairy - 4 Basball Card Pages (Cheese, Butter/Oil, Yogurt, Misc Dairy)
Dessert - 8 Baseball card pages (Cookies, Frozen Desserts, Cake/Brownie Mixes, Fruits/Jello/Pudding, 2 Drinks, Candy, Baking Goods)
Meat - 6 Baseball card pages (Fresh/Frozen Poultry, Lunchmeat, Breakfast Meats, Misc. Meats, Seasonings, Sauces)
Medicine - 8 baseball card pages (2 Cold/Allergy, Pain Relievers, First Aid, 2 Stomach Aids, Vitamins, 1-2 Misc. Medicines)
Paper Goods - 4 baseball card pages (Facial Tissues/Garbage Bags, Foils/Wraps/Containers, Plates/Paper Towels, Toilet Tissue)
Personal Hygiene - 14 Baseball card pages (Facial Cleansers, Body wash, Lotion, Toothbrushes, Toothpaste, Misc. Tooth products, Deodorant, Shaving Needs, Makeup, 2 Shampoo/Stylers, Hair Color, Personal Items, Misc. Hygiene)
Misc. - 9-10 Baseball card pages (Sauces/Salsa/Ketchup, 2 Canned Goods, 2 Frozen goods, Salads/Dressings, Misc. Foods, Pets, 1-2 Misc. Household Items)
You don't necessarily need the same # of pages I do! Customize to fit your needs!
Remember, I have to keep one of every current coupon - you don't!
TIPS:
90% of coupons will already fit the baseball card pages, If they don't slightly fold them w/expiration date showing if possible!
Insert Coupons with the product facing up - it is easier to find them!