Hi, if possable I need some help with coding.

This line of code sends a msg saying that DeliveryPhone=(delivery phone number.) From what I can work out the delivery phone number is found via the code $order->customer['telephone']

Code:
$plain .= "DeliveryPhone=" . $order->customer['telephone'] . "&";
The problem I have is that I need to send details of what is in the shopping cart ..... so the first bit of code is
Code:
$plain .= "Basket=" .
but for the life of me I cannot work out what the last bit would be. I have tried using $cart and others, I have also read about the possability of having to use $_session. I'm still very new to coding so any help would be appriciated.