I was renting a townhouse with a 12-month lease with a roommate in PA. 9 months into this lease, I needed to relocate due to a job move. I informed my roommate as well as gave a 30 day written notice to my landlord. The request was for my name to be removed from the lease after 30 days. It was unbderstood that my roommate (who was staying in the townhouse) would take over the full rent amount.

I recently received a letter from my former landlord. My roommate refused to pay remaining 2 months full rent, and as a result of not getting his money, my landlord did not remove my name from the lease.

A few questions:
1. Who is responsible for paying the remainder of the money owed?
2. Is it legal for my former landlord to keep my name on the lease even after a written request was given to him to remove it?

You are responsible for the rent until the end of the lease or until the place has been re-rented. You say it was "understood", but by who? Was anything in writing? What wasn't legal was for you to back out of a lease before its temr was up. A lease is a binding contract. The landlord had every right not to remove you from the lease.

Unless the landlord agreed in writing to remove your name ( and I don't know why they would since they want their money) you can't just give a 30 day notice on a lease, you are obligated for the full term of lease.

So yes, you owe your 1/2 of the lease for the full lease, unless they find someone to take over your rental