How to Add Google Buzz Button in Blogger:
Step 1: Login to Your Blogger Account.
Step 2: On Your Dashboard, Click on Layout (see below shown picture for further assistance)
Step 3:Now Click on HTML (see below shown picture for further assistance)
Step 4: Now Check the box of Expand Widget Templates (see below shown picture for assistance) Note: Before Applying Any Changes Please Download the Full Template for your Backup.
Step 5: Now you can add the Google Buzz Button either at the end of the each post or below the title of the each post.
Step 5.1: If you want to add the button at the end of each post then find this code in your template.
<data:post.body/>
Immediately After that Paste the code given below and Save your template and Done.
<div style='float:left;padding:2px;'><a expr:href='"http://www.google.com/reader/link?url=" + data:post.url + "&title=" + data:post.title' target='_blank' rel='nofollow' title='buzz this'><img alt='buzz this' border='0' src='https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhV5woYt7QL6Vb8NSk2fJQ9A5R2k36aj7LpP4s-MarI9neYNtieZH1_Iiyv9TCIdylsC7fNfOsVsHk3HoxjviUhyNkiico4Rlg1Xt-nUqbiMyEWK9ZIjkHsv1Nrk32cZJbZqf6m9Ux5O7_L/s400/Google+Buzz.png'/></a></div>
Step 5.2: If you want to add the button at the below the title of each post then find this code in your template.
<div class='post-body' entry-content'>
and immediately below it, paste the following code and Save your template and Done.
<div style='float:right;padding:2px;'><a expr:href='"http://www.google.com/reader/link?url=" + data:post.url + "&title=" + data:post.title' target='_blank' rel='nofollow' title='buzz this'><img alt='buzz this' border='0' src='https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhV5woYt7QL6Vb8NSk2fJQ9A5R2k36aj7LpP4s-MarI9neYNtieZH1_Iiyv9TCIdylsC7fNfOsVsHk3HoxjviUhyNkiico4Rlg1Xt-nUqbiMyEWK9ZIjkHsv1Nrk32cZJbZqf6m9Ux5O7_L/s400/Google+Buzz.png'/></a></div>

If you have any trouble while implementing the code then comment below. Have a happy Buzzing :-)