Manage Orders - Order ID and URL Order ID

I'm writing some code for an order summary, that links each order to it's page in "manage orders", so the admin can see the full order details. The url looks something like this


But the OrderID for an order is much longer and alphanumeric e.g. 894a77583be

My question is, how do i retrieve the order_id in the above url for an order? This will be the dynamic part in my code.