BROOK90 has been updated (2010 November 17). The current version is 4.4g, which I haven't downloaded to try out. I also haven't found a logfile that documents what changes have occurred over the releases. This seems to be a useful modeling tool, but also seems to be a 'one man show' and self-supported - which can be both beneficial and not beneficial.
Apparently a GUI version known as LWF-BROOK90 is available, but I can't find - and haven't requested - a download site