Well this isn't related to IIS.
You may try No ip.com forum/etc.
Anyway, your understanding of the concept is correct in a way that as long as you can 'uniquely' identify each of your pc via DNS/etc. then you should be able to reach them from the internet. Things you need to be aware are - firewall blocking, if PC is not using public IP, how do you forward the request to ther private IP of each PC and so on.