MultiCDBurn is a simple cd recording interface to mkiosfs/cdrecord that allows you to burn the contents of a directory and span multiple CDs without having to use an archive format. It will portion the files up into blocks of 650MB (or whatever filesize you set) and prompt you for blank CDs, burning them until all files have been done.
I was astonished that there was nothing out there to do this and I needed it for a customer project involving the archiving of lots of small movie files. They needed to be able to watch the movies direct from the CD (so archive/spanning was not allowed).
Requires Python, GTK and mkisofs/cdrecord (or cdrecord forks, such as wodim)