Would you like to show shipping methods of a one step checkout plugin after that a postcode is entered?
Go to the file app/design/frontend/base/default/template/checkout/onepage/shipping_method/available.phtml and replicate this file in your default interface/theme. Within the file, after (about line 31):
__('Sorry, no quotes are available for this order at this time.') ?>
Add:
getQuote(); $billAddress = $checkout->getShippingAddress(); $postcode = $billAddress->getPostcode(); /* 13-10-2014 Added requirement to enter postcode before shipping */ if (isset($postcode) && $postcode == "") { ?>
And close the else tag at the end. You can do this with countries, cities, etc. as well by changing the $postcode = $billAddress->getPostcode(); variable to:
$postcode = $billAddress->getCountry();
Good luck!