Thank you for the responses.

Primoz,
Indoogrid is overkill for this project but may be perfect for another project. Thank you for that link.

Bill,
Seeing how you used "GetModulePermissionsCollectionByModuleID" gives me the answer I needed. It is clear to me now that the UserID and UserName fields included in this collection are related to the new single user permission feature and not a listing of all users with permissions.

With that in mind, we will have to check for individual user permissions if we want to add them to the list.

   If mp.PermissionCode = Permission.Code And mp.PermissionKey = Permission.ModerateKey Then
      Dim RoleName As String = mp.RoleName
      IF NOT IsDBNull(RoleName) Then 
        For Each ui As Entities.Users.UserInfo In rc.GetUsersByRoleName(PortalId, RoleName)
          Dim li As New ListItem(ui.DisplayName, ui.UserID)
          If Not arrAvailable.Contains(li) Then arrAvailable.Add(li)
        Next
      Else 'If Role is Null then this must be a user permission
        Dim li As New ListItem(mp.UserName, mp.UserID)
        If Not arrAvailable.Contains(li) Then arrAvailable.Add(li)    
      End IF
   End If

"IF NOT IsDBNull(RoleName) Then" didn't work. For whatever reason they return a negative RoleID for the user permission records.

Replace the above statement with "If mp.RoleID > 0 Then".