Customized LiveUSB distro

[erupter]

I would like to know how and if is it possible to customize a distro to run live from usb.
I need to install some packages that are not default.
Is it possibile?
How?

I know there is an executable that makes every distro live to usb, it's available on the ubuntu main site.

Thanks

[Chame_Wizard]

It's possible.

Here (http://www.debuntu.org/how-to-customize-your-ubuntu-live-cd),here (https://help.ubuntu.com/community/LiveCDCustomizationFromScratch) or here (http://www.pendrivelinux.com/create-your-own-live-linux-cd-or-usb-distribution/)