a) Database Server
Either a FireBird or an Interbase database server is needed. The classic server and the super server builds are nearly equivalent for ibWebAdmin's point of view. Only the server statistics are not supported for the super server builds. ibWebAdmin is tested and kown to run with Firebird 1.0 and 1.5, Interbase Open Source 6.01, Interbase 6.5, 7.0 and 7.1.
You have to choose your database version on the database login panel to make sure that the correct and complete feature set for your database gets supported. The default server is configurable by the DEFAULT_SERVER setting.
These days most testing is done with FireBird 1.5 and Interbase 7.1 on a SuSE 9.1 Linux installation and with FireBird 1.5 on Windows 98 inside of a vmware virtual workstation.
b) Webserver
By theory it shouldn't make a big difference which webserver you are using as long as the server is supporting php in one or another way. In practice I'm only sure for apache 1.3 and 2.0. So it would be nice to give me a note if you are running ibWebAdmin successfully with another webserver.
If you are using ibWebAdmin through the internet you should consider to use an encrypted connection for security reasons, e.g. to use apache with mod_ssl. If you are accessing your database server throught the internet you can protect your sensitiv data by encrypting the tcp/ip datastream with the zebedee secure tunnel.
c) php
Beside of the webserver you will need php support, either compiled into the webserver or as a loadable module or as a cgi program. Every version of php4 greaten than 4.02 and php5 are ok. The php you are using must include the interbase extension, either compiled into php or as a loadable module.
ibWebAdmin is trying hard to take care for the various php configuration settings. But if you notice any troubles you should be save if you are going with the php.ini file that is coming with php named php.ini-dist.
d) Webbrowser
A recent Mozilla or Firefox, Netscape 6/7+ or Internet Explorer with javascript and cookies enabled are recommended. Any other graphical browser should work. But the dhtml stuff that is used to improve the usability is only available with the mentioned browsers. Cookies are used to store the user configuration between sessions.