A regular IRA account allows you to put
money in the account and defer paying taxes on your contributions.
Your contributions (and interest earned) will be taxed when you take
the money out. The theory is that in retirement you will likely be
in a lower tax bracket.
In a Roth
IRA, your contributions are included in your income and
you pay taxes on those contributions now. However, at retirement
you pay no taxes on the money you withdraw. So the original
contribution, plus interest earned, can be withdrawn without paying
taxes.