XML Photo Gallery with Thumbnails (Now need categories)

First post all.
Just wanted to say these are some really great tutorials. I’m in the midst of making a personal website and have really hit the grindstone designing a photo gallery. With the help of the tutorials I was able to create the gallery with thumbnails drawing from an XML file.

Now, before I go any further I would really like to know how to add onto this by giving it some categories. SO when a person selects the text (or button), the pictures switch to the appropriate category.

It doesn’t help that Actionscript and me go together like Oil and water…so any help would be greatly appreciated!

Thanks!:sen: