There had been an article in Fine Woodworking some years ago about creating a kiln out of roll plastic, a fan and an electirc heater. If you were drying a lot of wood, that might be the way to go. If memory serves me, it reduced drying time from a year to a couple of weeks.
Heres a link using an old freezer for a kilnhttp://www.ncwoodturners.com/tipsntricks.html
It looks like it work work well for the average plug builder.
There are a few references to using a wooden box with a light and a fan with the outside wrapped in foam board for a kiln on the net. Also a solar kiln could easily be constructed out of inexpensive materials. The biggest issue would be measuring the wood so that you would know when it was done.
How much wood do you have in mind drying?