Absolutely, they can. It's a fairly slow process with adults, but it's totally possible for both adults and kittens. My last cat was feral, and I've trapped hundreds of cats of all ages and "rehabbed" them, then re-homed after a spay/neuter. Many went on to become house cats, while some of the older ones became human-friendly barn cats. That last cat was about three years old when I started working with her, and it took a little over a month before she'd let me pet her. She became such a sweet, lovable pet (and yes, one that likes to be held and petted) that my ex decided to keep her -- it's been about 8 years and she's still an awesome pet. I've heard similar reports from the forever homes some of my "project kitties" went to.
Kittens tame a LOT faster, and have a higher success rate. I was just looking to see if I'd written a hub on the subject yet, and I haven't -- I touch on it in this one http://wychic.hubpages.com/hub/Solutions-to-Unwant... but I will add the caveat that I say most feral cats won't be tamed into pets because, in general, most rescue operations just don't put the resources into them. It's certainly not to say that it can't be done, because I have personally done it for many cats.