Very simple and easy to find out the sites and blogs that have linked to your site or blog.

1) By Google
Go to http://www.google.com/ and then type
link:yourwebsite.com

Above method will show duplicate results from same website though. Since in many websites the sidebar remains the same on all pages.

2) By Technorati
Copy the following in your Browser’s Address Bar and visit it, substitute yourwebsite.com with your website/blog address
http://www.technorati.com/blogs/yourwebsite.com?reactions