I am new to OpenID, and want to implement Google OpenID authentication on my website. I could not found any examples.
Can anyone suggest me some good tutorials (step by step) or any working example with code to implement Google OpenID authentication using PHP.
I'd suggest using LightOpenID. It's small, easy to use, and has working examples. You probably won't need a tutorial to use it.
Another answer suggests using php-openid, but in my opinion, it's too complicated and has too many dependencies (it is, however, more powerful).