My group has been roleplaying online for over a year now with very few technical problems. Just make sure everyone has headphones, a decent mike, and a private space/time (roommates have been an ongoing issue).
I think Skype requires a paying account to have multiple folks on at a time. Google Hangouts requires that everyone has a G+ account, which might be a problem, depending on your group. Roll 20, like WargameHub said, is a great resource, whether you're using it directly, or accessing it through Google Hangouts.