This article is from the Care of Orphaned Kittens FAQ, posted to rec.pets.cats newsgroup. Maintained by Sharon Talbert with numerous contributions by others.
While you are purchasing the milk replacer, find a good nurser. Most of these look like a baby bottle in miniature; I prefer the model with a pointy nipple. Pierce the nipple with a large-gauge needle (heated over a match) or ask the veterinarian to prepare the nurser for you. The nipple is constructed of tough stuff and is difficult to pierce; whatever you do do NOT cut the nipple with a knife or household scissors, however tempted you may be -- you may kill the kitten if you make the hole too large and flood its lungs. If you must resort to cutting, use a cuticle scissor and snip ever so delicately, then test (the flow should be a very thin stream) before offering the bottle to the kitten. If you did it wrong and made the hole too big, go out and buy another bottle or replacer nipple.
Other possible nursers are a 6-cc syringe or the kind of squeeze bottle used to dispense droplet medication (ask your veterinarian or pharmacist). These do present some risk, as the formula must be forced into the kitten's mouth, again increasing the risk of flooding the lungs. Last choice is a dropper, the slowest of the slow, but better than nothing until you go out and buy a nurser.