ZM: Roths are funded with after tax dollars. There is NO DEDUCTION on your income tax, however, the assets compound and are eventually dispersed without any tax liability.
Some regular IRAs have deductable features depending upon you qualifications. You may have been thinking of the "original" version of IRAs which under some circumstances are deductable but distributions are subsequently taxed.
Roths were created in 1998 and operated under slightly different rules. You may want to look at the articles at
www.rothira.com for more details.