I used to be a big fan of padmapper.com but since they have broken with Craigslist, the offerings are few and far between there. You might try one of the realestate websites like Trulia. You can look for apartmets for rent and they can also connect you to local brokers who can tell you about other places you may not have heard of.
In Monterey, generally, Craigslist migh not be so bad--though I find that website a mess, kind of like a flea market. You might find what you are looking for but you are just as likely to just end up with fleas.
