There are probably hundreds of publications on the subject. (Booch comes to mind.) Search the web for OOD (Object Oriented Design) and you will find lot's of it.
in reply to Re: Re: Re: Writing a web message board from scratch
in thread Writing a web message board from scratch
Booch, of course, being one of the authors of UML, the Unified Modelling Language. It's the industry standard for planning out projects and provides facilities for both broad-based planning and very narrow planning. Booch and a few friends came up with Rational Software, which produces a program called Rational Rose, the only Really Good (tm) UML design program.
Anyway, if you've got a week or so to do some research, you may want to look into UML and use it to design your project. Since it's for your company, rather than yourself, it may also help to use a standard design method, since the next guy that works on this project may not have a clue how to read your version.
Then again, the Perl code you'll be writing is job security, in itself, isn't it? :)
Just my dos centavos.