How to make a career working remotely?

This got me thinking about what I should pay attention to if I wanted to have a successful career working remotely. What kind of companies are more open to allow this form of work? How about freelancing? Are there any forums or groups online where I can find more information about working remotely? I have little idea about this as I have always been physically present at my place of work during the past 9 years of my professional life.