How to setup client portal

Question

How do I setup client portal with user name and password to each clients file for their view and/or adding a pdf or other document?

Answer 1

Could you put a few more words around the problem you're solving here, and some background?  (The answer to this question can range from a simple Apache directive to a huge content management system, depending on some of those details.)
How many folks are involved (and what's your likely growth rate)?  (Small numbers of folks can be managed manually, where larger numbers of users means different choices.)
Are you running Open Directory?  (Apache can be connected into that, and you can manage access from there.)
Are you looking for a web content management system (CMS) in addition to controlling access to specific documents, or just the authentication?  (Uploading documents generally means keeping track of the associated files and avoiding collisions, which is more complex and can potentially be risky - file uploads can lead to web server breaches, if they're not managed correctly.  In comparision, controlling access and allowing downloads.)
Web content management systems (which are more common choices for what can be called a "portal") have varying requirements and features.  There's a CMS matrix comparison site available.
For some of the core features, the 10.6 Web Services manual as a starting point, looking at the Realms-related discussions there, and potentially at WebDAV.  It's also possible to password-protect specific directories using Apache directives; that's the simplest, but it doesn't scale all that well.