Hi Jennifer,
Start with skin1/customer/main/cart_totals.tpl
Look for something like this:
Code:
<TD>{$lng.lbl_sku}</TD>
If you don't want the SKU label heading to appear, then either replace
{$lng.lbl_sku} with a or delete that line completely.
Then a little further on in the same file look for:
Code:
<TD>{$products[prod_num].productcode}</TD>
Again as above either replace {$products[prod_num].productcode} with a or delete that line completely.
Note: if you choose to delete on either one, you must do it in both places, otherwise your table/cart columns will not align correctly.