This tutorial is going to show you how to create text that looks like this:
 Step 1::
Step 1:: Open up the picture you want to use, I'll be using this:
 Step 2::
Step 2:: After your have it opened, go to 
edit > define pattern and hit 'ok'.
Step 3:: Open another document and type your text, I'll be using my site Unbreakable.
Step 4:: Go to 

 and click on 
'pattern overlay'. From here select the picture you defined as a pattern in 
'Step 2' and click ok.
 Step 5::
Step 5:: This step is optional, but I added a stroke around it, so my finished text is this:
 
If this helped, a 
link back is required.