I certainly don't use soap every time, but if they are in need of soap around here they get it (I am a big fan of clean). It is just really important that you heat them up a little bit after washing to open up the pours (put them in the oven at home or turn them upside down over the stove in camp). My Grandma always washed her pans (which I still use proudly - actually my favorite pan ) with the rest of her dishes, so I figure it must be OK as she did it for a lifetime.
As for the dishwasher - IF you must, be really careful. The heat dry cycle will take the patina right off of your CI pots and pans. I do not recommend this method at all for Cast Iron; however, if you are using Aluminum, there is no problem with putting them in the dishwasher.