Sub-categories and "optgroup"

[iantresman]

How about an option to specify a category to be a sub-category of the aforementioned category, and then use "optgroup" to produce a pretty select box,
Example,
http://imagegroup.com/presentations/webaccessibility/html-examples.html#optgroup .

[Ray]

You can create your own search form in HTML, as described in this FAQ:
Q. How do I put search forms on pages besides the search page? (Or define my own search form?)

In particular, see the subheading, "Defining a search form for a categories enabled website". You would be able to add optgroup tags this way to group your categories as in your example.