Looking at your other questions out here on WebmasterWorld, I'll assume you have little experience with your CMS, right ?
Now the good part is that I have no experience at all, so I can ignore that part completely and refer you to our content management [webmasterworld.com] forum instead.
Still converting an image in photoshop to a website is a lot of work, and often far from easy.
The first thing is that usually the image doesn't give a clue what should happen when content gets larger, nor when the viewport (window) get smaller than the content is, nor what happens when the user insists on a bigger font than your image wanted. Etc.
You're basically lacking a lot of detail for making it fit for web use.
Get those details and discuss them with however made the picture and whoever approved it.
Next in many cases it's overly graphic, drop shadows rounded corners, etc. and -most of the time- also often too restrictive by thinking only in terms of rectangular boxes (at least if it comes from somebody used to deal with table based layout)
Basically you try to make it doable with web technology (e.g. a drop shadow under a translucent overlay: all nice but it'll cost you a lot of time to fake such a thing.)
Once you have that, search for difficult parts (e.g. drop down menus) etc and get the mechanics behind it right (plenty of examples around), and finally style them to look right.
As you build more of these components your page will slowly grow into existence.
Now comes the part where you modify your pages (html and CSS) into a template for your CMS ...
[edited by: swa66 at 3:34 pm (utc) on June 6, 2009]