Seems to me I have heard of a braille reader for computers. It attaches as an external peripheral, similar to an external keypad, but has a smooth surface with holes that pins are pushed up through in a pattern depending on the letter being read. I will attempt to try to find some reference to such a device.
In the mean time, I will also post here any of the other references I find while searching for "braille + computer" ...
Woodlake Technologies - appears to be speech to voice conversion.
About Braille - An educational page about different types of braille.
International Braille Research Center - Fascinating information and additional research links.
Trynameks - This looks the most promising so far. There is a listing for braille displays, but, unfortunately, when I clicked on it, I got a message that the page was being updated.
Robotron - A braille palmtop device.
ScreenReader.co.uk - Various products available. Didn't get into it deep enough to verify whether they offer a braille reader, but it looked like they might.
Blindness Resource Center - This site has a lot of information and resource links. It is also the first one I've seen that had a "braille" link.
Sighted Electronics -
FINALLY! Success. There are several braille readers available here. They've come a long way from the (obviously prototype) one I saw which only displayed single letters.
Hope this helps.
[Added]
I continued looking and found the following that may be of some interest:
BrailleNote - A standalone braille "keyboard" thay may also be used to interface with a standard computer.
SensoryTools - Offers several touch sensitive devices, including a talking compass!
Louis Braille - A short history of how Braille notation came to be.
FreedomScientific - More products offered for vision impaired users.
BRL, Inc. - More products for visually impaired. I thought their domain name was rather catchy, WYFIWYG = What You Feel Is What You (Get?)