Hi patideee. Let me try and shed a little light on the situation.
You're are connecting to someone else's wireless internet access. Who ever they are, they have not password protected this wireless connection and therefore you're able to connect to it. It is a very bad idea not to password protect such a wireless connection. Unfortunately a lot of people don't even realize their connection isn't password protected.
firstly, am i being charged for this service?
No, someone else is paying the bill. Hopefully they're paying a flat rate monthly fee and not for the time spend online.
do i no longer need my other (basicisp.net) provider?
That depends on your morals.
You can of course not be certain this wireless connection will continue to be available.
am i tapping into a neightbor's road runner service?
Sounds likely.
Can somebody tap into my computer files?
That is always a possibility. A the very least, going online via an unprotected wireless connection lets anyone see what web pages you visit.
and just now my telephone rang and i didn't get knocked off and i was able to talk on the phone while i was still connected to the internet
That's because you're not connected via your phone line but through a wireless receiver/transmitter built in to your computer.
If you want help disabling this wireless connection please tell us what version of windows you're using on your computer. (probably XP or Vista)