Not any one website, because the auditions occur locally, regionally, and nationally. Several production companies have their own websites and don’t broadcast widely. I suggest you ask your agent to do the work for you.
Yes, as stated by YARNLADY—locally. As you live in LA this should be fairly easy.
But not to be rude there are already SO many actors/actresses in the world it’s kind of a chore to keep up with all of them and it’s really annoying so I just stick to my few select faves (Uma Thurman<3).