Looks like you've had a lot of "answers" -- I am not going to read all of them, but I have done this easily without experience, and its turned out just great -- if the doors are unfinished (unpainted) pine, get a medium reddish brown "mahogany" stain, and apply with a brush, leave on a minute or so, and wipe with a cloth to remove excess. If not dark enough, repeat the process. If still not dark enough, or too red for you, then get a medium or dark brown stain, and apply this -- it's best to "try" this out on a sample piece of pine first, so you will have an idea of what the finished doors will look like. Once you have the look you want, cover the finished product with a poly sealer, available at home improvement stores. Good luck!
