Hi Barb - Although I don't live in an area where there is a need to worry about moisture, that concern was every day when living near the Gulf coast in Texas. I started saving those little silica gel desiccant (actually crystals)bags that come in electronics and pills. I throw them in with my router bits. Have never had a problem with rust or corrosion on those bits, although once a week I had to re-wax the belt sander table. Exposed shafts on the bandsaw and sander also started to rust.
Here's a handy thing to throw into drawers and chests.
http://www.hartvilletool.com/product/11481