I need help figuring out a way to create this explorer/browser for a webpage.

The website is for buying pre-written letter templates. I wanted to be able to create a java/flash/etc item that would allow the customer to browse through the letters by subject, then based on a letter they select they will be able to see a description of the letter.

I have a picture of what i had in mind. Here it is:


I am not sure what code would best fit an item such as this or how I could implement it into the web page. I was hoping some coding pro's could help me out and give a few pointers. Thanks