Extract that ISO with Winrar into a temporary directory, mnaking sure when you go into the Extract screen that you check the Advanced tab and that "Extract Relative Paths" is selected. It should be by default. Once everything is extracted, go into that temporary directory, hit CTRL-A to highlight everything, then click Add. On Split to Volumes, bytes, you can select a pre-determined size or enter your own. A CD-sized volume should be split into 10,000,000 byte sections and a DVD-sized one 50,000,000. I'd also download Quickpar, add all the RARs you make, and make 10-15% parity files, in case some of the RARs get corrupted during storage.
