Here is another article that details the construction of a USB radio interface from a SYBA UAUD71 USB sound adapter. This one makes use of Chuck Kelsey's circuit board and an inexpensive plastic case.
http://www.repeater-builder.com/voip/voip-index.html
Scroll down to the bottom of the page and click the SYBA UAUD71 link.
(other articles for other devices are also listed)
Comments, questions, and constructive criticisms welcomed in private email.
Thanks,
Kevin Custer - W3KKC