We used when we want to install any software for our web servers or any of our development machine is to read alot of KBs article how to install .Net Framewort 3.5,SQL 2005 express edition...etc. and it was a long process you have to have your DVDs or download it from your partnet account website,then start your software installtion process.
Microsoft has released a new wonderful tool,to prepare all required software for installations on your machine,it shows you all available SW based on your machine OS and architecture (32 or 64bit ) and make it available on a list.
The new tool called "Web platform installer",and you can download it from the following link:
This tool should be used by .net web developers who prepare their web server or system admins.
The tool has alot of sensitive tools and updates,the person who use it should be aware about the tools and the conflict that might happen.
I have used it and it's pretty easy and fast :).