You are correct ceh4702 in stating the quality depends on the sound card, but if dydt is just trying to pipe live radio broadcast from the internet to her stereo almost any sound will be adequate.
dydt first in order to do this check your sound card hopefully it has a line out connector. This...
The cable you are looking for is called a Null Modem Cable. Windows 98 has the software built into it to connect it this manner. It is labeled direct cable connection I think. It has a long time since I have done it, but you also have to remember to share the drive that you want to push data to...