to create a wishlist, you will need to first add user registration to your store using security assist, see the "Applying Register/Login to your checkout" tutorial on the eCart support page.
When the user logs in, a session variable will be set to hold the UserID.
next, create a wishlist table to associate the UserID to the ProductID added to the wishlist
wishlistID - int, Primary Key, Auto Number
wishlistUserID - int, Foreign Key - Relates to the users.userID column
wishlistProductID - int, Foreign key, Relates to the Products.ProductID column
On the product detail page, add the Add to wishlist button.
add an insert record server behavior that is triggered on the add to wish list button to store the userID session variable and the productID in the wishlist table.
you can then create a wishlist display page by createing a join query to join the wishlist table and products table on the ProductID column, filter the wishlist.UserID column on the userID session variable.