I am out of shape, and haven't done much biking, ever. I'm also planning a tour for this spring/summer. I've started riding the wind trainer (the roads aren't conducive to riding for a workout on) and doing a few other exercises recently.
Last fall I took the longest trip I'd ever done (~58 mi) and was completely wiped out at the end. My legs wouldn't make me go more than 10mph at the end...
I did recover pretty quickly... (I'm 21), but I don't think I could have done much riding the next day...
I'm curious about what others have done to prepare for a tour. Do you get in very good shape? Do you not worry about it, and just get in shape while touring?
If you are out of shape at the beginning, how does it go? Is it pure agony, or is it tolerable? Are you exhausted all the time?

I'm interested in advice and tales from experience....