external taxonomy links

Google is your friend, try searching for "drupal category link to external URL".

The Link module (http://drupal.org/project/link) looks like a possible. Depending on the version of Drupal you're using (always include this info when you ask how-to questions) the solution could take several different forms.

No worries, I'm just trying to help you find the resources you're looking for. Posting questions in Drupal.Groups might not always work.

In terms of Drupal 7.7 and linking a category term to an external URL. I would:

1. Add the Link module as detailed in my orginal reply above
2. Add a custom field to the category term admin/structure/taxonomy/category name/fields of the type Link
3. Customise the term output / markup to make the term link on a node page point to the link field value rather than the default taxonomy term listing page.

This is my solution, of course there's always more than one way of achieving the same results in Drupal - that's the magic! If you happen to find another method please post it here so others can enjoy your efforts. If you find yourself stuck please ask more questions but not after doing a few Googe searches :)