Since April 15 falls on a weekend, the IRS extended the deadline to file taxes this year and New Yorkers have until April 18. Some people may find they still need more time and extension forms are available on the IRS web site. To apply for the six-month extension, Brooklyn residents need to fill out form 48-68 by April 18 to avoid late fees. The IRS says the most common mistake people make on their forms is leaving out their social security number. They encourage people to file online to avoid errors. The IRS will prepare low-income Brooklyn residents? taxes for free.