Here is an easy to follow, yet poorly written, guide (that includes links to software) of how to create a bootable cd:

http://old.bink.nu/xpbootcd/

Basically use the winimage program to extract your .iso file, select "Bootable CD" (or equivalent) with your burning software, tweak the setting as shown in the pictures, then burn.

Note that this is how to make a bootable Windows XP cd, however it does say "...or you have an ISO when burned to CD does not Boot?" so I am assuming this will work for any iso.... but no guarantees.