If the contents of the directory fits on a single CD, then you can simply use K3b. If not, you could use tar and split, or a backup program like kdar. I saved the contents of my home directory before installing a fresh install of SuSE 10.1 on my laptop. I used tar and piped the output through split so I could save it on an external USB harddrive. The harddrive was used a FAT filesystem, so it had a 2GB filesize limit. I was able to restore by using cat and piping the output of cat into tar to extract just the files I wanted to, and I did not have to reassemble the
tarfile. The tarfile never existed in whole form.
The dar program is similar to tar, but it works better if you are using CDs or DVDs for the backup media. The kdar program is a KDE graphical front end to dar.