Apple will hold up to 30% of what they owe you for tax purposes unless you can provide an EIN number to apple to claim the tax treaty benefits.
But the information from this article only applies to developers who operate under a company, so if i am self employed and work individually how can I claim the 30% withholding tax?
I'm self employed and based in the UK. You can call the IRS in the US and apply for an EIN. That's what I did. More details in this forum post.
Follow the same steps in the O'Reilly article you linked to... It would be the same process whether you are an organization or an individual.
Apparently you can also just "enter nine zeros (000000000) in the space provided in section 6. In addition, payments from the USA App Store will not be reported to the IRS on form 1042 at year end."