Are you waiting for an extension help you easily in changing the look of your PDF Invoice? We will provide for you the best PDF Invoices generator. Have a look with our extension then you will know what are we doing ...
Go to http://www.magentocommerce.com/magento-connect/catalog/product/view/id/14411/
After you install this extension via magento connect go to System->Configuration->PDF Pro
On General section enter API Key: TRIAL_LICENSE_2012
This is only trial version so you will not able to change the logo in PDF file and invoice template
The Full version will be released soon.
A sample invoice : invoice2012-09-14_22-21-04.pdf
We are coming soon !
Fee free to let me know if you have any question.
Easy PDF Invoice Team