You need certain tools to make a Kiss doll. Go to The Big Kiss Page, and look through the tools section for a very comprehensive guide. It doesn't have everything out there, but it comes very close. There are very few Mac tools in existence, but if you use a PC you will have more of a choice.
If you are using a Mac, there are 3 things you must have:
Some version of the Frenchkiss viewer for Macintosh (there is only one real program, created by John Stiles. There are different versions, the most recent by emk). I would recommend to have one of the earlier versions before emk took over, it makes some of the creation aspects a lot easier. You may also wish to have an emk version for some extra effects.
A text editor (I use SimpleText, unless the file is too large, then I use Microsoft Word. I recommend SimpleText over Word)
I also recommend having the following programs:
Graphic Converter (graphics)