Howtoforge published a guide about creating Ubuntu 7.10 or Linux Mint 4.0 Live-CD with Remastersys

This guide shows how you can create a Live-CD from your Ubuntu Gutsy Gibbon or Linux Mint 4.0 system with a tool called remastersys. Remastersys is available in the Linux Mint romeo repository. You can customize your Ubuntu/Linux Mint system and then let remastersys create an iso image of it which you can then burn onto a CD/DVD.

Creating Your Own Custom Ubuntu 7.10 Or Linux Mint 4.0 Live-CD With Remastersys