THE IRS DOES NOT COMMUNICATE VIA E-MAIL!
If you receive such an e-mail, do NOT click on any links it may contain. Either delete said message unopened, or forward it to firstname.lastname@example.org so that their fraud department can deal with the perpetrators.
"Verifying" the sort of information such forms request can allow the perpetrators access to your funds and your financial information. With that information, these people can not only drain your bank account(s), they can also open fraudulent account in your name, running up debts which you will then have to contest or otherwise legally handle. This can range from an annoying hassle to a (potentially very) expensive legal undertaking. Do not be taken in by such scams!
If you've already been fooled by such a tactic, I would advise you to contact the IRS (if their name was used), and possibly your local District Attorney's office and/or your local FBI office (as such schemes are legally classified as wire fraud and thus fall, at least partially, into the FBI's jurisdiction). Any of these offices should be able to help you, and such services are part of what you pay taxes for.