Drupal Multi-Site

Drupal has the advantage of being set-up in a multi-site environment. These modules provide for the ability to run multiple Drupal sites either of the same code base or the same database (example: each domain has its own db prefix etc).

Reference links:
http://drupal.org/project/domain

Some Tools/Tricks that may help
Allows for the creation of Drupal multi-sites on local machines http://drupal.org/node/166831 this can be useful if local developers need multiple copies of drupal on there local machines