As more and more people are upgrading to V3 I thought it was about time to complete the redirection kit which will help you minimize any effects the link changes might cause.
The script is available for download at the end of the post, this only works for people who have the seo pack. If you are upgrading from v2 to V3 but never installed the seo pack you do not need this and it will probably cause problems trying to use it.