If you just got started with OOP in PHP, I suggest not to use any frameworks at all, especially not CakePHP. Last time I checked, CakePHP was backwards compatible with PHP4. OOP in PHP4 is different from OOP in PHP5. PHP4 is officially dead.
While I am not saying CakePHP is a bad framework (I've been quite productive with it on one occasion myself), I've seen code reviews by experts that do question CakePHPs code quality and have ranted about it on more than one occasion.
Also, keep in mind that frameworks have to be learned too. And while they will make you more productive eventually, you are less likely to learn OOP concepts and Design Patterns from them, because you are focused on how to use the specific framework over understanding why the framework works a certain way. The point of a framework is not to teach you OOP, but to ease and solve certain common problems in web application coding.
To cut a long story short, if you want to learn OOP, start simple. For a start, try Sitepoint, TuxRadar or buy a good book. Once you've learned the fundamental concepts and the most important Design Patterns, move on to frameworks.