Please elaborate on your environment, do you hav a single (dev) box environment or are you trying to add  users thru web-interface on your corp team site/portal.

Not quite sure how and where you want to add users  to your site, there are multiple ways (like directly on the site  or thru Central admin (for Administrators type users)).

Following are some ways to add users:

Add a site collection administrator
1. In Central Administration, on the top link bar, click Application Management.
2. On the Application Management page, in the SharePoint Site Management section, click Site collection administrators.
3. If the selected site is not the site for which you want to manage administrators, on the Site Collection Administrators page, on the Site Collection menu in the Site Collection section, click Change Site Collection.
4. In the Select Site Collection dialog box, select the site for which you want to manage administrators. Click OK.
5. In either the Primary site collection administrator box or the Secondary site collection administrator box, enter the user  name of the user to whom you want to assign that role. Click OK.

Set up Members, Visitors, and Owners groups for a site
1 On the site home page, click the Site Actions menu, point to Site Settings, and then click People And Groups.
2. On the People and Groups page, on the Quick Launch, click Groups.
3. On the People and Groups: All Groups page, on the Settings menu, click Set Up Groups.
4. On the Set Up Groups for this Site page, select a group for each set of users that you want to change. Alternatively, select Create a new group to assign a custom group to a set of users.
5. After you have configured groups for the site, you can add users and grant them permissions by using the following procedure.