Collecting and using user profile information has always been a popular aspect of the Drupal module scene. The Profile module (part of Drupal core) has always been a relatively straight-forward way of collecting additional profile data about users, but its lack of default Views and CCK integration has been problematic for most users.
Saving user data as nodes has been possible using a variety of methods for quite a while, but it seems that with Drupal 6.x, things are coalescing around the Content Profile module. This allows you to set a particular CCK content type as a user profile (the module actually creates a default "profile" content type automatically for you) - thus gaining all the advantages of CCK and Views (and their associated universe of modules) when dealing with user profile data. This is extremely powerful and lets you do all sorts of wacky things with your user's profile data (don't be evil).
This article talks about the (relatively easy) process of getting the Content Profile module configured for a Drupal 6.x site. Then, I'll go through the process of making one of the profile fields available to Views and a template file for use when displaying a node. This might be useful if one of the Content Profile fields you're collecting is a short biography of the user that you want displayed within any nodes the user has authored. Then, your standard node view can look like this: