You can download the Corporate Clean .psd files directly from Drupal project page http://drupal.org/project/corporateclean using the "PSD Template" text link. More Than (just) Themes hosts the .psd files. For your convenience, here is the download link http://mttdownloads.s3.amazonaws.com/projects/kaolti/corporateclean_psds.zip
Additionally you can find the PSD files at the designer's website http://kaolti.com/?portfolio=corporate-clean
Furthermore, we have prepared for the community a Drupal 7 demo instance with Corporate Clean theme and demo content here http://demo.drupalizing.com/?theme=corporateclean
Our Corporate Clean theme is fully documented. Find out how to reproduce our Drupal 7 demo instance here http://wiki.morethanthemes.com/index.php?title=Corporate_Clean:Demonstration_Content_for_Drupal_7.x
