Compressed Encoded Video on Web HTML Sites and HTML DVD

[AutahG]

I create picture & video sites on the web for friends & family events.
Mostly using Photothumb ( http://photothumb.com/ ).

The Photothumb creations are all HTML based & load/Autorun from CD/DVD
into whatever browser the user has installed.

The pictures & video clips come off my Fuji S602Z & F30 cameras.

The video AVI files are HUGE! They are useable on DVD copies. But
online they load at unacceptable speeds.

I am looking for suggestions as to the codec/encoding technique that
will work both online and from DVD. Best wide ranging standard
useable on many platforms. From multiple browsers. From multiple OS.
Windows. Linux. MAC. etc. Also how do I pass the codec to the
online/DVD so that the user can readily load & read the coded AVI
files.

Thoughts appreciated. - Art