The Cat's Fancy by Julie KennerRead about the other entries on the list.
Nick is an attorney who's engaged to marry the uber-bitchy daughter of his boss. His black cat, Maggie, is totally devoted to him and hates Nick's fiancee — so she decides to do whatever it takes to keep Nick for herself. She somehow convinces the magical Old Tom to transform her, so that she appears as a naked woman on Nick's doorstep. By day, she's a cat. By night, she's a naked lady stalking Nick. She has one week to get him to say he loves her, or she loses. But she still sort of has the mind of a cat. Read here for an excerpt, including the great scene where she crawls around on all fours, still naked. Later in the book, she forgets she's supposed to be human and starts eating kitty treats. By all accounts, this is a fun paranormal romance... as long as you don't think too much about a guy and his pet cat hooking up.