My question involves landlord-tenant law in the State of: Pennsylvania

We have two cats on the premises which were okay-ed by our landlord. Our charge was a $100 non-refundable fee as well as $20 extra a month. When our lease renewal came around, it specifically said a charge of $0.00 (which was subsequently signed by both me and the landlord), so I haven't paid the extra $20.

This passed month they started to ask about it. I told them that I would need a new form reflecting the $20.00 pet charge on the lease before I gave them the $20.

They sent us a new lease renewal form with the same duration as our most current lease renewal (July 1 2011 - July 30 2012). The only thing that has changed between this new lease renewal and our previously signed renewal is the pet charge. I see no legal obligation that I have to sign this renewal.

However, there's a clause in the pet agreement we first signed saying all the things are pets shouldn't do (disturbing other tenants, damaging the apartment, etc) then the last line says:

Quote Quoting Management
Management may revoke the consent given herein upon 7 days written notice, which revocation will require you to remove the pet from the premises within said 7 days or your right to occupy the apartment is subject to termination.
Does this mean that they can ban our pets without reason? More specifically, if I do not choose to sign the renewal can they just go around and say, "Well, then you're not allowed to have the pets here anymore."?

Secondly, I have been trying to leave this place for awhile now (I actually posted a thread about it in the Moving Out Forum). I have heard a claim that -- in my state -- if you're given a modification to the lease, you're allowed to reject it and move out after giving your landlord notice. I haven't read anything to substantiate this claim. Also, since we're still under our 1-year I don't think the act of management sending me a new lease cancels our previous one.

However, there is this part in a letter they sent with the lease renewal:

Quote Quoting Management
If you do not plan to renew, you must give a 60-day notice to vacate prior to your lease expiration date (Me: which is July 30 2012). Notice will be accepted as the first (1st) of the month following the date the notice was received.
So maybe there's some truth to it? What do you think?