I read it I think about 4 years ago.  It was about some sort of village or monestary of female magicians, I don't remember what they were called, and they were guarding against a dragon (or more than one).  At least one of the dragons could turn into a man, and I think he may have fallen in love with one of the priestesses (for lack of a better title).  Then they found that the head priestess had been trapped in something, a tomb maybe? by someone else who was using her appearance and really taking over.  I think there was a woman on the cover and it was light colored.

If anyone can help me identify it, I'd appreciate it!

-Rebekah

I'm pretty sure you are talking about Mistress of Dragons.by Margaret Weis. Its the first book in the Dragonvald series.