I play a LOT of blindfold chess
I've played a few ok people (best I've beaten is 110 grade ECF) and once done a simultaneous blindfold agaist two not-especially-good people.
I tried a bunch of programs to help with visualisation, but basically, they don't work. I may team up with a programmer from my school at some point, and get him to make something that would be helpful, but until then, don't bother with all the computer stuff.
Things to do instead:
1) Find someone else who wants to learn blindfold. Then you can get a blindfold, and take it in turns. Allow yourself to take off the blindfold after 20 or so moves, and finish off a game as normal. This is just practice with your friend. You aren't displaying anything yet, and it helps.
2) Play a few games not strictly blindfold, but with your back to the board, staring at a blank one. I started off like this. It helps an awful lot, and you can very quickly find it easy to picture where everything is.
3) In your spare time, imagine simple situations like a lone rook on the board, or a bishop and a pawn. Try to visualise exactly what squares the pieces can move to. How fast they can get to certain squares.
4) Start visualising harder situations, and compose simple mates in 2 in your head. Play through some basic endgames; King and Rook V King.
Some things NOT to do:
1) Worry too much about working out notation. It takes me quite a long time. Questions like "Is D5 black?" or "How quickly can white get a knight to G6 from the starting position?" are often asked in these software trainers, but they help with nothing. When I train, I do similar questions, but I think "Can the black squared bishop get there?" or "How quickly can my knight get to there?" Instantly picturing the square without any notation getting in the way. Notation clouds your memory. In a game, I have to use notation, but I see this as a method of distributing information rather than a method of storing information. If you try and run over a position, and your first thoughts are "right, I've got a knight on f6, bishop on h4, king on e4" you will find it very very hard.
2) Don't play over the game to recall where something is. If you're in the middle of the game, and suddenly think "oh goodness, is there a pawn there, I can't remember," then it is very tempting to start building up the game from the start to check what's happened. Don't! You will forget much of the rest of the position and this will often be more important than the pawn. I instead do a sort of mindsweeper tactic, and label that square as blue, assuming there both is and isn't a pawn there (in other words, assuming it can capture diagonally, and assuming pieces can go through it) until either a) it moves or b) your opponent moves another piece through that square. These things will answer your question, and you will have continued safely.
Hope these things help. I will try and think of more rules I've developped and work by, and will answer any questions you have about it