My roommate signed a renewal on both of our behalfs when our first lease ended. I had vacated the apartment and asked what needed to be done to have me taken off the lease and was told that I needed to do nothing that my roommate just needed to come sign the renewal and the lease would only have his name on it. Now the apt community is telling me that he signed a renewal with both of our names on it and that I am responsible. I never signed or saw the new lease and have not lived in the apartment since the last lease ran out. Is this legal?

No, it's not legal - a lease is a contract and no one can sign a contract for you unless that person has your power of attorney.

Nope. Unless he has a Power of Attorney, he can't sign for you. You should have, however, sent a written notice to the landlord that you were not going to renew the lease.

Send them a letter stating that you never signed the renewal nor authorized anyone to sign for you.