I've been using one since I started this thread, and it works pretty good. It took a couple weeks for it get rid of most of the moisture, but now it seems to just maintain low moisture levels.
+1 on the rechargable dehumidifiers, it might take a few rechargings early if its pretty damp but then they last a while. Depends on how well you seal your kegerator and how often you open it up.
There are some silica gel desiccants that you can bake in your oven to drive off moisture. They turn blue to pink or something when its dry/not dry. Probably those rechargeable ones people are speaking of.
i never tried damp rid becuase of claims that it was messy and combersome to deal with, thats why i bought the rechargable units. so far vr happ with them.