C#.net setup and deployment proejct files

In a new C#.net 2008 desktop and console application that I need to setup for user acceptance testitngm i would like a suggestions on the following:

1. In the setup proejct file, would you include the .net framework 3.5 as part of the package If so, how would you suggest this be included in the deployment project? (There should be some logic in the install package for it to check if the the .net 3.5 is already installed) If not, would you just tll the network adminsitrator to check before he installs the new application on users's desktop?

2. At my company various users have windows xp, windows 7, a few other verions of the Microsoft operating system. How would you handle this? Would you setup different installations packages for the various versions of the operating systems? Would you include the different operating sysytems in the same install package?

3. Users would like to have shortcuts on their desktops to run the new application. How would you handle this situation?