I own an OSCommerce natural skin care store - eveorganics.com.au.
A few months ago I had a module added to my OSCommerce store which allowed people to enter their email address in the description for an out of stock item, so that they can be notified when it comes back into stock. To make the email field appear in a product description, I enter the product quantity as '0' in the ctrlpan.
To make the email field disappear and to automatically notify anyone who's requested to be emailed when it comes back into stock, I update the quantity again to '1' - and the module sends the emails automatically.
It's very clever - and from the product description page, it doesn't allow customers to add the item to their cart when a product is out of stock (which is good, since it's out of stock).
However, from the category page where products are listed side by side, a customer can still click 'add to cart' and purchase an out of stock item.
I would like to make it so that a customer CANNOT purchase an item when it's out of stock (ie, when the product quantity is set at 0 in the ctrlpan). I just don't want the 'add to cart' button to be available to them.
Having people order products which are out of stock is causing me a lot of trouble!