Here is a quick tutorial on how to add your own custom button to Google Toolbar. I decided to pick something extremely simple for my first article. There's not really even any coding involved, just a simple XML file and a link!

You will need to compose an XML document. Google will use this to create the button. It's nothing fancy - really! If you don't know what XML is - don't worry about! To start take a look at the contents of Green Marines XML file:

  <?xml version="1.0" ?> 
- <custombuttons xmlns="http://toolbar.google.com/custombuttons/">
- <button>
  <site>http://www.greenmarines.com</site> 
  <title>Green Marines</title> 
  <description>A free community for US Marines.</description> 
  <update>http://www.greenmarines.com/updated_button.xml</update> 
  <icon mode="base64" type="image/x-icon">
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+PkA6unrACwmLAAsKCwANzM2 ADo1OgBFQUQAvLm9AFJOUQBYVFkAcm9yAHl1
eAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA A
AAAoQEpDQUXL7B/AQEBAQEBAQFhnE1Jr1d5cWwBAaOiogGLIVAgnRiWQAafeA
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AAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAA=</icon> 
  <feed refresh-interval="1800">http://www.greenmarines.com/MemberBlogs/tabid/67/rssid/0/Default.aspx</feed> 
  </button>
  </custombuttons>

• site - The location the browser will be directed to if someone clicks your button
• title - The name of your button
• description - Keep it short, this will appear when your mouse hovers over the button on the toolbar
• update - the location of the XML file
• icon - base64 encoded representation of your button's icon
• feed - an RSS or Atom feed added to your button (required if you want to submit your button to the Google Button Gallery) You can add more than one too!

You don't need all of them. The main ones are in red above. Just replace the values between these tags in the XML with your own. To base64 encode an image for your button, determine or create your image. (I used Green Marines favicon.ico since it will be made 16 x 16 pixels anyway). Then use this page to encode your image. Copy the result into the image element of your XML document.

If you have an RSS or Atom feed, insert the URL of your feed into the feed element. Save your document with an .xml extension (we used updated_button.xml). Copy the XML file to the root of your website directory. It's ready to go!

Now, just add the below link to your site, where ever you choose and when people click it, they will get your button added onto their Google toolbar:

http://toolbar.google.com/buttons/add?url=http://www.yourwebsite.com/yourbuttonxmlfile.xml 

Replace the url= with the fully qualified public url to your xml file. If someone clicks the link and doesn't already have the correct version of Google Toolbar installed, they will be prompted to install the correct toolbar.