I attended the symfony training day in London to learn some of the goodness that seems to be symfony in the PHP world. The training was great for 150 pound I was able to spend awhole day learning about creating some basic tasks in symfony from framework structure, to project set-up and templating.
The best place to start for understanding Symfony is with the cookbook
This will take you through the basics and also how to set-up the framework and get started on creating some bundles, understanding the controller and templating. If you are located in a place where they are holding Symfony training which seems to becoming abit more often and I have no doubt will be more available with the uptake of the framework I would suggest a training day. The basic training basically covered the stuff in the cookbook with a couple of more advanced steps. The other training they offer is the advanced training which is better if you have an idea of symfony. In hindsight I would of done the cookbook prior to the training and actually attended the Advanced however I really wanted to get more of an understanding of the workings of the framework and came armed with some questions on why X is done X and not Y. Allover a good day with the Symfony Live Conference to follow tomorrow.