A very good solution to this problem is Backup 3. Backup 3, however requires a dot Mac subscription to use.
FGDataBackup is a free alternative to Backup 3. It is, however, a bit of an odd bird as far as Mac applications go. First off, it doesn't look like any Mac application you've ever seen because the author saw fit to design his own look. Second, the text is half in English and half in Italian. Don't let that deter you, however, if you don't speak Italian. I don't, and I was able to figure everything out just fine.
What FGDataBackup does is what Mac OS X won't do– Backup files to CD or DVD and span that backup across multiple discs as needed. For example, a DVD holds 4.7 gig of data. If you want to make a copy of your iPhoto Library and it is larger than 4.7 gig, you will need to span your backup across 2 or more DVDs.
Even though the interface of FGDataBackup is odd, it is easy to figure out. You tell it what folder you want to backup and whether you are using CDs or DVDs. It looks at your folder and tells you how many discs are needed for the backup and then burns them one at a time.
At the end of your backup, you will have one or more discs and the files from the folder you backed up are spread across those discs. If you ever need to do a restore, you can just copy the files back using the Finder.
FGDataBackup is free and runs under any version of Mac OS X. Download FGDataBackup here
Download FGDataBackup here.