You just want to compress them so you can send them to another computer and extract? If so, I recommend using zip files. http://www.7-zip.org
No, if I've understood correctly the compressed files are too big and he wants a way of prompting to insert the second disk after the first.
However, you can use 7 zip to split the compressed file up into 2 sections, see here
for how. It won't prompt you for the next disk, but will prompt you for the next file (you're not going to get something prompting you for another disk unless you look into writing your own installer or similar.)