OO Design Formally

Hello PHPers, I've been doing the programming thing for about 10 years now: amateur side gigs turned into ten years pretty fast. I think i have a fairly strong sense of object oriented design, data modeling, etc... However, sometimes I wish I had a stronger academic understanding of the design / planning phase of new systems. Then I could be absolutely certain my design is correct before investing mega $ and time into the implementation phase. I think I'd save myself a lot of time and frustration if I could improve my designs before I started coding...obvious right? Well, i've read the wikis, the forums, the blogs, etc... I think i need a text book. I'm looking for an OO design methodology recommendations which focuses on churning out reuseable / flexible deliverables. I'm not afraid of getting all academic about it either. It is about time I really got down into the nitty gritty of "proper" OO design methods. I'd appreciate any recommendations as for improving my OO design approach/methodology. Thanks, dK `