Is it bad to let her cry for long periods of time, like 5-10minutes straight?

I have a 6 week old that has become accustomed to people sitting and holding her. Putting her down for naps and at night is kind of hard. It even poses a problem at the baby sitter. How do I break this and begin to teach her how to fall asleep on her own? I was given advise to let her cry herself to sleep but that is heart wrenching and makes me feel bad. Any suggestions? And she won't take a pacifier.