Tutorials:Calculating Hash Sum
Requires installation of freeware program: http://www.softpedia.com/get/Security/Security-Related/HashCalc.shtml After installation drag ISO onto Desktop shortcut and it will auto generate the MD5 sum.
Ubuntu and similar flavors: https://help.ubuntu.com/community/HowToMD5SUM
NOT recommended for the ISO, will take too long to upload, but for other files if needed.
Online option for smaller files >1MB (you upload the file): http://www.hashsum.com/