I've had a few people ask how all my posts have the graphics on them...

First step is to click on your gamertag (that is what you used to create an account, isn't it?) in the upper right hand corner of this page.  In there you'll find a signature text field.

Here is the text that is included in my signature (as of this writing):

Cory Smith aka DualBrain
<a href="http://www.addressof.com">AddressOf.com - .NET Developer Blog</a><br>
<br>
<img src="http://card.mygamercard.net/gelsig/DualBrain.png"><br>
<br>
<img src="http://miniprofile.xfire.com/bg/bg/type/2/dualbrain.png">

As you can see, I've got my real name (not required of course) associated with my gamertag.  The next line is just a simple link to my personal weblog for development topics.  Noticed the returns (<br>).

Now for the meat of the signature and the ultimate answer to the question.  The first image is retrieved from http://www.mygamercard.net.  You can go there and create one as well and they have a few styles you can choose from.  The second image is pulled from http://www.xfire.com; of which they have an application that is very similar to XboxFriends for the Desktop except for PC games.  So if your a PC gamer as well, now you know. ;-)

So to duplicate this for your own signature, just go to the mentioned sites and get your images created.  From there, replace the ones I've highlighted and there you go.  Now you have not excuse not to have a cool (and informative) signature.  If you have any questions, please let me know.