I can relate to how difficult it is to find a rental when you have pets. When I relocated from Mass to St Louis MO, giving up my 2 German Shepherd Dogs was simply NOT an option. Finding a rental was difficult, luckily (for everyone!) we were able to find a house to rent for a year. The landlord had said "dog allowed with approval", he only approved my 2 big dogs after seeing proof that I was a responsible dog owner. Letters of reference from my veterinarian, both dogs had their CGC (Canine Good Citizen)
AKC's Canine Good Citizen® (CGC) Program Sponsored by K9 Advantix®
which is open to mixed-breed dogs as well as pedigreed champions, and one dog had an advanced obedience title. Even with all of this, I did have to pay a full month's extra security deposit, which was returned in full. If you can prove to the property owner that you are a responsible pet owner, they're much more likely to rent to you.

Bonne Chance!
THE LINKS:
Apartment Rental and Hotel Directory accepting Dogs, Cats and Other Pets
petswelcome.com Rentals
(this is just a back-door into a realtor.com site, but it pre-screens for pets allowed. Keep in mind that the contact on this site will be the agent representing the property owner. You may chose to have an agent represent YOU (which BTW, is free)
Boston Pet Friendly Apartments Rentals
PET FRIENDLY APARTMENT RENTALS (nationwide)
Traveling with pets:
DogFriendly.com(TM) - Pet Travel Guides and City Guides for Dog/Pet Owners
pet friendly travel, pet friendly hotels lodging, pet friendly vacation rentals, pet travel
petswelcome.com
BringFido.com - Pet Friendly Hotel & Lodging Directory