Right click on the setup project.
Go View->Launch Conditions.
In the Launch Conditions Window, you can see
1. Search Target Machine
2. Launch Conditions.

Do the following
1. Right click on the Search Target machine and choose View->Add Search File. Now, search for file will be added.

2.Right click on the newly added item and choose properties.
In the property window, add filename that should be installed when installing .net framework and add folder property.

Ex:

FileName : readme.htm
Folder : [ProgramFilesFolder]\Microsoft Visual Studio 8\

Now, build setup and install. Take a look on Custom Action for uninstalling operations.