From No Box Solutions:
Agent Aware is a Windows Forms tool that allows users to view the static or dynamically generated HTML output of a page based on the user-agent string. Agent Aware users can request a page using any of the pre-configured user-agent strings or create their own user-agent strings. It lets you see the html output as it is rendered by the server using technologies like PHP, ASP, ASP.NET, CGI, or Perl and sent to the client. In addition you can view request and response headers from any Web server such as Apache, IIS, or Sun as well as view detailed information about the requested page. It allows users to view external script files or style sheets that are referenced in your Web page as well as any images.