ADSI.....................................

Can you please clarify, mass  upload meaning you want to provide the
permission/access for mass set of users  in sharepoint site.

Yes, I want to provide a mass  group of users  access to sharepoint site
including adding them to the necessary groups.

For WSS 2.0 en-masse adding see the following:

See:

"SharePoint Account Management using SPUserUtil - Part 2 - Adding
Accounts"

blogs.msdn.com/.../602057.aspx

I no longer do further enhancements to it, but there was never really
any support for it either except direct mail to me.

I've heard that the author of that tool suite is a pretty rockin' developer

Rockin' and rollin' with permissions management.

Active Directory or SharePoint Groups? Are the users  already in a
datastore with an Authentication Provider like Active Directory? You'll
need to add them there first.

You can get a script that will create users  in Active Directory (with
passwords) here

You will need to bespoke it a bit (for example, this creates the
accounts disabled) or you can run as is and just enable all of the
accounts by way of marquee select

whitepapers.techrepublic.com.com/abstract.aspx
=300111 or http://tinyurl.com/37ffft