Without knowing your budget, I'll pass these links along. At the very least, they will give you some ideas of really neat properties and what they look like.
I stayed in a lovely little place called Roko House a few years ago (inside the fortified city). I found the place on Splendia.com. The lady who owned it was incredibly nice. It was technically an apartment, not a B & B, but centrally located and really bright, neat, and clean - a little small though, but that was fine by me. It cost about EUR 95 per night, but that was a few years ago in September (shoulder season). Some places can get quite pricy (and many have just a few units at a certain price) so I would recommend finding one that fits your budget early and reserving it.