you can start learning yii from book also from google. Best site for yii is yii website.if you have any problem regarding yii then just write your problem in yii forum.You can also visit my blog for yii solution.
As written many times on this forum, if you did not yet read it, the best way to start with Yii brefore reading anything else is to read the Definitive Guide to Yii - http://www.yiiframework.com/doc/guide/It will give you all the basics of Yii and reading and understanding other posts/tutorials/videos and so on will be much easier for you.