Imtech Solution Setup is a tool that installs and deploys SharePoint 2007 solution files (.wsp). The tool works in two modes: setup and standalone.
The standalone mode is meant for "each day" use: after starting the tool you have to select the .wsp you want to install. Then you have to select the Web Applications where you want to deploy the selected .wsp to and click "Setup".
In the setup mode the "Browse..." button is disabled: the .wsp has been passed to the setup tool as a command line argument. All the user has to do is select the deployment target(s) and click "Setup".
Although this tool is not extremely powerful and customizable its light weight and simplicity make it works for me. It turns pretty handy in MSI-kind installers.