1. About 3 dozen Chinese Prefold Diapers--4x8x4 in the Infant size. We used both bleached and unbleached, but my heart belongs to the unbleached now. They're softer and more absorbent.
2. One dozen diaper inserts. We used the flannel version first and, even after trying others, we still like the flannel best. Again--it's softer and more absorbent. Make sure you check the size--you'll want to get the smallest available for a brand new teeny tiny.
3. About ten diaper covers. This is a tough one to pin down, because every baby is going to go through them in their own very exciting manner. If the baby simply goes peepers, you can reuse the diaper cover, as long as the diaper didn't totally soak through--use your own judgement here. If they load up their tiny pants with gooey poopers, you're going to need to bust out a new cover. Start with about ten--if you need more, you'll know pretty quickly. I like bumkins covers best, followed by ProRap.
4. Roughly three to four dozen cloth wipies. No sense in using disposable wipes with cloth diapers when cloth wipies are so easy (and save you a ton of money). Again, our preference is for the unbleached cotton.
5. Find a good diaper pail. We inherited the one my mother-in-law used with her kids and it's awesome. If you can't find one you like, check with the diaper services in your area--they might sell the ones they provide for their customers. If all else fails, a garbage can with a diaper pail liner will work just fine.
6. The bumGenius diaper sprayer. You need this. You do not want to do cloth diapers without it. Trust me.
7. A waterproof bag for diapers that get soiled while you're out and about. A plastic grocery bag will work just fine in a pinch, but, since we use cloth grocery bags, we don't have a lot of plastic bags hanging around. We only have one waterproof bag right now, but I'd really recommend getting two. That way, you have one to use while you wash the other--and they do need to be washed often.
When you get all your diapers stuff home, toss the diapers, inserts, and wipies in the washer. You'll need to wash and dry them three or four times to get all the natural oils out. If you bring your baby home and find the diapers aren't as absorbent as you'd like, run them through another wash/dry cycle. After you've washed and dried the diapers a couple times, fold them and stack them neatly in a basket or a drawer. Hook up the diaper sprayer and make sure it works. Put your diaper pail next the toilet that's got the diaper sprayer. Now, have a baby so you can use all your new stuff.
If this seems daunting, call in a professional. Waddle yourself down to your local cloth diaper retailer and start asking questions. Don't stop asking questions until you feel confident. If you can't find a shop you're happy with, call me. If you don't have my number (or you don't know me), call Wee Bunz (1-800-WEE-BUNZ). They're available Monday through Friday from 9am-6pm PST and they will make sure you have everything you need to get started.
...and it is daunting. On top of everything else--what with the having a baby and all--it's just one more thing you have to learn. There's a learning curve while you figure out the best methods of cleaning, washing, and folding, but it all comes together quite quickly. After thirteen months of cloth diapering, I can say with absolute certainty that I wouldn't have it any other way.