Attached is a sample xls to upload products and categories from the cart admin menu
Here are SQL statements to add some things not included in the spreadsheet:
UPDATE Smith_Products SET MaxOrderQty=-1
UPDATE Smith_Products SET DownloadUrl='http://acme.com/Product1Download.aspx' WHERE ModelNumber='Prod1'; UPDATE Smith_Products SET DownloadUrl='http://acme.com/Product2Download.aspx' WHERE ModelNumber='Prod2'; UPDATE Smith_Products SET DownloadUrl='http://acme.com/Product3Download.aspx' WHERE ModelNumber='Prod3'; etc.