Infantino just recalled one million baby slings after the slings were found to have led to the death of three babies. When you are caring a baby, it is hard to get much done with your hands tied up, so a sling makes great sense. You can keep your baby close while still getting to use your hands.
Many people love to wear their babies, and a sling allows that. Some people also use front or back carries, but there is all sorts of controversy about those causing problems w/ infants hip development.
I actually did use a front carrier for my infants, and when they were bigger and sitting on my hips, I used the sling to support them upright on my hips. I'm not sure it was the best way, but they both made it at least.
So, how on Earth are you supposed to carry your baby safely? Do you have a way? Did you use a sling or carrier to carry your babies?
See http://www.cpsc.gov/cpscpub/prerel/prhtml10/10165.html for information on how to use baby slings.