Yes, if you really get it.
It helps you visualize how parts of a larger system can interact with each other. It's very useful at the design level.
If you are just writing a few lines of code, the only benefit you will get is that it is generally a little easier to use a library broken into well-designed objects than just functions.
To make good use of it, you also need to follow sound OO design practices. Always encapsulating ALL your data, using many small classes, never large "catch-all" classes. Having the class do your work for you instead of asking it for data and doing the work outside the class, etc.
It's probably not going to help you much for a while, and possibly never if you are always doing small websites (I can't say this for sure, I don't really do php), but over time and on large projects it can be invaluable.
