There is a CD-ROM called Twain's World.  I have a copy at home,
but I forget the issuer.  It's one of the major companies--
Bureau Multimedia, I think.  It's pretty ubiquitous at computer
software shops.

It offers decent texts of Twain's novels, some speeches & short
stories, etc.  Although the texts aren't based
on the definitive California editions, they're plenty good enough
for all casual users and most scholars.  The CD has a pretty
flexible searching capability, which is what I use most often--
it's an invaluable tool.  There's also some miscellaneous stuff,
including cheezy animation and a short film of Twain allegedly
taken by Edison.  All in all, a great addition to any library,
especially since it's under $50.

Scott Dalrymple