ISAServer.org has published a guide for creating an ISA reports web server. It is a quick and easy solution to making the reports available to managers and other interested parties.
For my ISA Server deployments I like to take it a step further and use a little ASP code to generate some nicer looking tables that are a more visually appealing than the IIS directory browsing view. Just follow the instructions from ISAServer.org, and then drop the ASP file into the same web folder on the IIS server. You may also need to enable the Active Server Pages web extension for the IIS server.
The report page will look something like this.