Drop down list

[alemica]

Hi, if someone knows please tell me how can i make a drop down list with subcategory and one with product for each subcategory.Example:

First drop down list
Category Warcraft in this page drop down with: Please select a server
Subcategory: Server1, server2, server3, etc.

Second drop down: Please select product

If server1 was selected  show the product for this server
If server 2 was selected show the product for this server and etc.

Something like this but without ALL list:
http://img692.imageshack.us/img692/1159/28284663.png
http://img29.imageshack.us/img29/7687/ex1i.png
http://img696.imageshack.us/img696/7691/ex2sr.png


Thank You.