Hi,
Why not make use of the categories and secondary categories function in the admin area?
Create all your categories including your shop by brand and shop by category and put choose the relevant place for each product?
Thanks for your reply. That is fine, but I need to create 2 separate menus not one. Is there any way to do that?
You should be able to do this by creating the appropriate product features and then product filters. Then create a new block in Design->Blocks with:
Content: Product filters
Filling: Filters and then set the filter to show in the Specific Settings.
Bob
Many thanks Bob. Fantastic Idea. That worked. Great! 
Hi bob,
Can you elaborate on how to use product filters and product features to pull this off? The documentation is **** when it comes to these features and I’ve been racking my brain for days trying to figure out how you use these. What IS a product feature? I understand the product filter to be like [$0-$100] , etc, but can you give an example of how you would use a product filter to create a shop by brand?
A product feature is anything you choose which can apply to products -it can be manufacturer, specifications (length, width, 5-channel, 7-channel). Product features are created in Catalog->Product features.
You create product filters using the Catalog->Product filters link. There you can assign what value (feature or product field) a filter uses and which categories the filter applies to.
You can find a specific example here:
[url]http://forum.cs-cart.com/showthread.php?p=63332#post63332[/url]
Bob