Create a .RAR that's .ISO

Will this automatically happen when I add any directory to a .rar? See I have a bunch of files which I need to burn as an ISO image but I'm not sure what's the best way to do it..

You need to rephrase, that doesn't make sense... If you want to store an ISO as a rar, you first need to create the ISO, then you would need to use winrar to create a rar file.

Common tools for creating ISO's are Roxio or Nero. Once you create the ISO, you can then Add it to a RAR archive... Winrar would give you the option to break it into sections also if you like.

If you have many RAR files, which are in small sections containing one large ISO, then you just need to make sure all the RAR files are complete, then open any one of the RAR files and extract to a directory... This will extract the ISO as one file from all the sections.

If you specify more exactly what you are trying to do, I could offer more accurate advise. I'm also available on AIM if you need help.

You can use the CDR Tools Front End for windows (it's free) to create ISOs:
http://demosten.com/cdrfe/
(the site is frequently down)