Swazoo is an open source, vendor-agnostic, dialect-neutral Smalltalk web server with resource and web request resolution framework.
Its main features are virtual site support, clean web request parsing framework, static web serving, input streaming of HTTP requests (for large file uploads, output streaming (chunking) for responding large files and for Comet.
The Swazoo download for Cincom VisualWorks 8.0 contains all the prereqs it needs (i.e. over and above those that are still in the standard VisualWorks installation).
More about Swazoo: http://www.swazoo.org.