It's easy to create and add "applications" in BrowzOS, with a little knowledge of web design. Given the availability of web design templates, this task becomes even easier.
Don't be afraid to use this page as a template, either; open this file in an ordinary text editor and have a look at the different HTML elements. This can prove quite helpful (especially with regards to including icons within an "application" window; the necessary PNG image rendering fix for Internet Explorer 6 and icon dragging scripts have been embedded in this page, for the sake of convenience).
Creating icons in your "application" is also a matter of using the file desktop.html as a template, though.