how to apply single page checkout using drupal ubercart I am using Drupal6 with ubercart.I want to apply single page checkout instead of multi step checkout. When I checked the ubercart features it provide the one page checkout in features lint but  I am not getting idea how to use this feature.Is there  any module for it?

I have a package functionality in my site.There are three package silver,gold and standard.I want user can choose only one package at a time and user should be not able to add more package in cart if the package is already in cart and if user has already that package?

Please help waiting for the response.

Thanks in advance.
Yo cant make it single page. Mandatory steps are,


Add product to cart
Go to checkout page
Payment 


You can combine the steps 3 by adding Shipping and billing address using Ubercart Checkout Tweaks module, which helps to

Assume billing and delivery addresses will be the same


  In many stores, orders are delivered to the billing address more times
  than not. Enabling this option in the checkout settings will default
  the "same address" checkbox at checkout, making the checkout page seem
  shorter and less intimidating.


For limit the products that added to cart you can use hook_add_to_cart

Parameters:
$nid - the node ID of the product
$qty - the quantity being added
$data - the data array, including attributes and model number adjustments