I always travel with plenty of zip-lock plastic bags of the larger sizes. I put dry cloths (tee shirt material is great) inside these bags. Besides being able to wipe mist off your gear with the dry cloths; you can always pop the camera, lens or other equipment inside the bags for protection.
I have also purchased, but haven't as yet used (Southern California is in a drought) plastic Rainsleeves manufactured by OPTECH. It looks like these might work O.K. to protect the camera/lens from spray, rain and mists. They are pretty inexpensive. There are other, more elaborate and also more expensive covers available.
http://www.penncamera.com/store/index.asp?DEPARTMENT_ID=394&pg=all covers available on the market.
Some camera bags such as Lowepro, have rain covers built in. However, you can always protect your camera bag with plastic garbage bags and gaffers tape.
It is my experience that you can fairly easily protect your equipment from the drizzle and rains in our temperate zones but, it is pretty difficult, if not impossible, to afford total protection from tropical monsoon rains.