I'm pretty fucking jealous! I used to walk daily and sometimes do a 7 or 8 mile 2.5 hour treks just for fun. Unfortunately, I developed Plantar Fasciitis this last summer. Hurts like crazy. Walking from the bed to the toilet in the morning was the most painful. (seems the plantar tightens up at rest)
So yeah, I haven't really walked much since then. Motrin, Aspirin, Aleve are my friends now rotated daily in order to reduce inflammation with the hopes of someday being able to walk distance again.
So just a bit of advice. Be careful my friend. Walking may seem easy but repetitive pounding of the pavement can very quickly ad up.
I would suggest you consider looking at some web sites on proper walking techniques and even consider hiking sticks.
There are no free lunches -- walking improperly can injure knees, joints, hips and back. If you are really bad at walking it can also damage you brain much like the brain injuries distance runners experience. (about the same as boxers)
So I highly encourage your new found walking behavior, but I also encourage that you do the basic research in order to determine proper technique and equipment.
Walking rocks! Wish I could do it.