Public or Shareware LISP Programs

[Bruce Lester <72110.1107@CompuServe.COM>]

I have MCL 2.01b and am in the process of learning LISP.  I have been working 
through a introductory textbook on LISP and plan to also work through "Object 
Oriented Programming in LISP" by Sonja Keene.

I am looking for examples of large LISP programs and a utility to diagram CLOS
class hierarchies.  I noticed that the "Getting Started with Macintosh Common 
Lisp" manual mentions that "...extensions, third-party code, and patches..." 
are available for downloading from this bulletin board.  How can I get a 
directory of what is available?  Can I download using Compuserve's Internet 
Gateway?  Are there other sources of public domain MCL LISP code?  Can I use 
standard virus detection software on LISP code that I download?