First of all, if you happen to use cloth diapers, you can throw the pads in with them and wash them in the same ways. Simple!
For those who don't have a cloth diapered heiny in the house, I'll run through the basics of cloth menstrual pad care. There are several basic parts (numbered), and several extra, optional steps (in italics)...so feel free to use these recommendations as you prefer.
1--after use, I rinse the pad out in the sink with hot or warm water, then place soiled pads in cold water in a container with a lid. Most women keep a small tupperware or ceramic pot under the sink or on the back of the toilet. So long as it has a lid, it will not smell. (Some ladies like to put tea tree oil, lavender essential oil, hydrogen peroxide, oxy clean, vinegar, or a little soap in with the water.) If you are out and about, just put the pad in a waterproof bag or pouch, and put it in the water when you get home.
2--refresh water once a day to prevent odor.
3--wash on hot (some ladies swear it has to be cold to prevent staining, but I have never had problems), rinse at any temperature, dry in drier (or hang dry). Do not use any type of fabric softener.
4--if, somehow, something did get stained, let it soak in hydrogen peroxide or oxy-clean for a few hours. It'll come out (at least, it always has for me!)
Pretty simple, huh?
A while ago I saw a pattern for a washable knitted tampon. It was brilliant--it rolled up for use, unrolled for washing, and was knit in pretty cotton colors. I am thinking of doing some experimenting to try to create some for my shop, but I am in no hurry. I (like many others who prefer internal menstrual protection), have a menstrual cup. (I like the diva cup, though there are several brands out there.) I'll write about cups sometime soon.