What do I have to do to sue someone for money owed?

I got my friend and her husband two lines from verizon wireless like a year ago now the owe $500 and say they wont pay it, verizon cut their lines and now they got another month to month phone, also a few months ago they went in a verizon store and extended the contract on one of the lines without my permition, I want to know what do I have to do to sue them for the money owed to verizon plus the early termination fees that are going to be applied.

Go down to your local court house and file a small claims case against them. You can usually sue up to 2-3 thousand dollars-depends on your state. Get all your records together and all the info. from Verizon especially the extended contract!!! You can also go for penuitive damage if this is going against your credit report!!! I would also go down there in person and shut off the new line!!! It only cost about 30-40 dollars to file!! Good luck