Howard,

For RTTY I use the free MMTTY software:

http://hamsoft.ca/pages/mmtty.php

As you would expect, tuning in the signal, and getting your screen 
reader to spit out something understandable is the hardest part.   Do a 
simple audio connection from radio to pc sound card and play around. 
Once you get the rx side working, than you can decide on how you want to tx.

With JAWS, I found that putting a frame around the rx window and 
setting it up to read incoming text works pretty well.   Otherwise use 
insert-s to "all" to read incoming text.

Good luck, Steve KW3A