Yep, Cydia is a clear indicator that the phone is presently jailbroken.
Originally Posted by Antarktikali
Cydia by default has the community sources which should give you enough to be dangerous and get some third party software onto your phone. Take a look at the repository section, there are additional sources in the Cydia library that already exist in your list that you can add for additional package types and additional software.
If you're referring to "free" iTunes / App Store apps, please don't. Piracy isn't condoned or supported here. Discussion of it will lead to warnings, thread closings, and bans. If not, sorry for the knee-jerk -- there's a lot of it running around this week!