Google for 'Pauls ATA driver newton' and you'll find it. Its not free, if I remember right its something like $60. There is a demo, but it will only let you use 4mb of the card.
Again, google to the rescue. 'newton wifi driver' should be suffice. Also, not free, and it can no longer be bought (the dev went AWOL). After 30 days you can only use it on 100% open networks, and there is no stumber.
Not one that any computer can read. The only way to get info onto a newton formatted flash card is through a newton.
Hope that info helps, if it is a bit unfortunate.