Add an InstallShield LE project for a Windows Service

First you must have a windows service project with a ProjectInstaller class added to it.

Then just add a new project and select the InstallShield Limited Edition Project template.  Walk through the wizard (Project Assistant) and just add the project output from your windows service project.  You do this on the "Application Files" step.  Just click the Add Project Outputs button in the lower right hand corner.  Click the Primary Output check box as shown below:

Then, in Solution Explorer, double-click on "Files" which is under "Specify Application Data".  Right-click your project output, and choose properties.  You'll see this.  Just check that Installer Class checkbox, click OK, and you're good to go.