Are you meaning to basically self-publish them?
If so, there are some software programs out there that will distill them to a .pdf format for you, but the best (in my opinion) is Adobe Acrobat.
Acrobat Reader is free, the full version of Adobe Acrobat is not. I don't remember how much it is right now, though.
When you open up Acrobat Distiller to convert files to a .pdf, it will ask you if you are doing an ebook or something else. I've only seen the dialog prompt box a couple times, so I don't remember exactly how it's worded.