I have been reading that Kohana is good for my project. So now I want to get started. My PHP knowledge is 2 years old and very limited now. But I am experienced with object oriented programming and other patterns, since I develop in Objective-C. I know a little bit about databases.
People told me the Kohana documentation is horribly poor. So, where do I start as a newcommer?
this might not be the best way but 1. i watched the 2 tutorial videos on the codeignitor framework and tried a small example 2. i switched to kohana and tried the same thing and haven't looked back
i am quite familiar with php, so your mileage may vary
As mentioned by petsagouris, the 101 wiki is a good resource for seeing examples of how to use the framework. It's also worth reading the docs as well. Even though they aren't as good as CI's they still contain a lot of useful information.
However if you want to get the most from the framework I recommend you invest a couple of hours looking through the code of the classes that you use (e.g. Kohana, ORM and if you're feeling brave, Database).
The files are very well documented and the experience will help you solve problems more quickly as you will know how Kohana works, and where to look if something isn't quite working as you expected.