On Sat, 1 Mar 1997 07:14:17 -0800, you wrote:

>Can anyone recommend a low-cost (under $500) PC-based oscilloscope?
>Just plan to use it to help debug PIC circuits, especially serial comms.

There are a few written for linux that are very lo-cost(free). There
is usually a fairly simple circuit to go with them, that should pose
no building problems. I never actually tried to get one going but just
remembered it being interesting. I think they are somewhere on
http://sunsite.unc.edu/pub/Linux 

Might not be exactly what you are after but worth a look.

Regards
Simon