The person to talk to is Graham Cluly, who produced a couple of
adventure games under the name "Humbug Software" and apparantly managed
to sell several thousand shareware registrations.
If you grep the rec.arts.int-fiction archives for him, you'll find some
posts from him describing how he did it.
However, the market has changed. When companies like Sierra can
allocate a $4 million budget to games like the recent "Phantasmagoria",
with more than 50 people working full time on the project, what hope do
amateurs have?
-- Gareth Rees