Drupal Customizing User Registration Form

I am newbie in Drupal 6. I am looking for customizing User registration form.

Apparently found that while adding user using Admin login allows registration form to have fields like email address, username, password,confirm password, etc with validations. But when anonymous use wants to register, then only fields like email address and username are displayed.

I tried with Profile module available. But now how could I add some fields (password, confirm password, terms & condition check and receive news letter check box)and behavior (password, confirm password validation etc.)?

If I am adding such fields they 开发者_StackOverflow中文版are also get visible in Admin>>Add user form resulting duplicate fields like Password,Confirm password.

Could you please suggest me how can I do this? I tried googling but confused me a lot as I am beginner to Drupal.

Just for reference, If anybody wants to customize "Create new account page" (by default D6 allows you enter user name and email address, and initially sends confirmation email with inbuilt password) with setting password (D6 only allows while admin(or user having permissions) logged in) functionality, can use LoginToboggan module.