use a cart repeat region.
On the Server Behaviors panel, click the plus button and select eCart -> Cart Display -> Repeat Cart region.
Assuming your cart name is eCart1, the code should look like:
<?php
while (!$eCart1->EOF()) {
?>
pageTracker._addItem(
"1234", // Order ID
"<?php echo $eCart1->DisplayInfo("ID"); ?>", // SKU
"<?php echo $eCart1->DisplayInfo("Name"); ?>", // Product Name
"<?php echo $eCart1->DisplayInfo("Category"); ?>", // Category
"<?php echo $eCart1->DisplayInfo("Price"); ?>", // Price
"<?php echo $eCart1->DisplayInfo("Quantity"); ?>" // Quantity
);
<?php
$eCart1->MoveNext();
}
$eCart1->MoveFirst();
?>