This tutorial will show the steps to follow in order to customize an Ubuntu Live CD to your need by removing some component and adding some others.
Read it at Debuntu
During this tutorial, we are going to remaster our Ubuntu Gutsy Gibbon 7.10 Live CD with the following spec:
remove non english language pack
Update the softwares release shiiped in the live CD
Enable universe and multiverse repository
Include divx, mp3 support, realplayer ….
Include ndiswrapper support
Add Firefox flash-nonfree plugin, add skype.
Add some network troubleshooting tools: traceroute, wireshark, kismet…
The resulting image will be bigger that 800M, so it won't fit on a CD, but will be fine on a DVD.