Multi step user registration form drupal 6 How to do Multi step user registration form in drupal 6 ?

I am having an idea of doing multistep process using custom form.

But i am bit confusing while doing the same case with "user registration".

For example :

Let us consider i am having 10 fields and separating it with three forms like 4+4+2.

Now when i complete the first form and click next button where should i need to save the values of current form. I used $form['storage']. But it didn't helps.

Could anyone please clear me this or provide me an easy tutorial for "multistep user regsistration".

Any help will be thankful and grateful..

Thanks in advance..
This blog post may help you: Multistep registration form in Drupal 6