Burning DVDs seems to be quite easy.
Use the dvd+rw-tools package, which is conveniently apt-getable in Debian. Then simply type the following command
growisofs -Z /dvd/device -R -J /path/to/files/for/dvd
growisofs will automatically take care of building the iso9660 image and writing it to your DVD drive. Everything after the /dev/device specification is mkisofs options which are passed through explicitly.
You can also create multi-session DVD+R's and add content to DVD+-RW disks using the -M option to growisofs.
So for example to create daily backups for a project I'm working on I execute the following commands
growisofs -Z /dev/device -R -J --graft-points 20051201=/home/model
growisofs -M /dev/device -R -J --graft-points 20051202=/home/model
And so on until the DVD is full. I end up with folders for each date on the DVD and within each folder is the contents of /home/model as it existed at the end of the day. Each backup is stored in a separate session on the DVD.
I've only tested this with DVD+R format DVDs and the DVD reader in my IBM T42 laptop. I'm not sure whether separate sessions are supported by other readers/writers but it works for me.
Obviously you should consult the mkisofs(8) and growisofs manpages for more info.