When migrating from Drupal 5, the normal path would be to migrate everything (core/modules/themes) to the latest Drupal 5 versions, and then to the latest Drupal 6 versions, and then over to the Drupal 7 versions. How fortunate would have been the developers assigned the job if everything was as simple as that!
Drupal 5
Drupal 6 was released on Feb 13, 2008, 13 months after Drupal 5 was released. Extending that estimation Drupal 7 should be out around March or April 2009. That is around 8-9 months from now, Drupal 5 will become obsolete. There has been talks going to extend the support life cycle of Drupal 5 beyond the release date of Drupal 6 but nothing as of now. We are happy to announce that we will be able to support people who would like to convert Drupal 5.x modules to Drupal 6.x. If you want help to port a Drupal 5 or Drupal 4 module to Drupal 6 contact us to get a quote for your requirement.