I've been looking for a program like this for awhile and came across this http://www.sminstall.com/ It'll create a simple easy to use install package for say maps/mods you release... I have the full version and really love it, easy to use and makes the person downloading have to do nothing but install... Plus with cross OS's it automatically will direct the files to the correct program folder locations steam uses... If anyone has a better program list it...
That is all enjoy!