How do I extract a boot image from a bootable CD/DVD using K3B?
Or is there another KDE app to do that?

Thanks.

for extracting files from iso's you can be use Dolphin if kio_iso is installed, the disk will be under /media

There are some standalone apps for working with iso's:
- Kiso (it's a kde 3.x app but should run if the kde3 libs are installed) http://kiso.sourceforge.net/
- AceToneISO http://www.acetoneteam.org/index.php
- IsoMaster http://www.littlesvr.ca/isomaster/

acetoneiso did the trick. And it's included in ubuntu repo.

Thanks again.