I signed a lease and paid 1st month rent and pais security deposit. Today (the day before the 1st!), our property manager called and told us that there was a misunderstanding. They had signed a lease with another family for the same house. So even though I have paid over $2,000 to move in and signed a 12 month lease I can not move in tomorrow. What are my rights?

They owe you a place to move to, or need to cover your expenses until you find a place.

You will probably have to sue them. But they will be required to pay for storage of your things, a hotel to live in etc until you find a new place.

I signed a lease and paid 1st month rent and pais security deposit. Today (the day before the 1st!), our property manager called and told us that there was a misunderstanding. They had signed a lease with another family for the same house. So even though I have paid over $2,000 to move in and signed a 12 month lease I can not move in tomorrow. What are my rights?

They are in breach of contract. The only real question would be the measure of damages. Clearly you have the right to a return of what you paid, and any incidental expenses. Anything more is problematic.

Also if another place that is about the same costs more to rent, you may even sue for those damages also