Gonzalo Ayuso has posted a wrapup and the slides from his SOLID presentation at this year's deSymfony conference recently held in Barcelona, Spain.

Last saturday I attended to the deSymfony conference in Barcelona. A great opportunity to meet again with the PHP and Symfony community in Spain. This year the conference accepted my talk about SOLID and Symfony. Here you can see the slides of the talk (slides in spanish). [...] The conference was perfect. Barcelona is an incredible city and the conference place (10 minutes walking from the Sagrada Familia), was incredible too. Great talks. But the best, as always, the coffe breaks with the conversations with the Symfony and PHP community from Valencia, Zaragoza, Madrid, Barcelona, ...

His talk (in Spanish) covers some of the basics around the SOLID design principles including definitions of each piece and brief code snippets to illustrate. If you're interested in a bit more detail around the SOLID principles in PHP, check out the first four parts of a series over on NetTuts.com for each principle: Single Responsibility, Open/Closed, Liskov Substitution & Interface Segregation and Dependency Inversion principles.