The habari-dev group and user group are must read before you start trying installation of a test site at hosting. The project site is here where you also find wiki (not much) and downloads.
I would recommend anyone to try installation at localhost first. I did that under XAMPP version 1.5.4a with PHP 5.1.6. I recommend that you check rewrite_module is enabled in httpd.conf file of your Apache before starting. Without this you won't even see the installation screen of Habari. Next would be creating a MySql database, it's harmless to use 'habari' as its name but this default entry in the installation screen is confusing as the AJAX check isn't quite ready so it's still OK to proceed even if you see "failed" and a message that your database can't be detected...etc. For more details see this thread.
With the experience at localhost I proceeded to installing a test site at my hosting Site5. See this thread if you want to know what silly things I have done.