If  tax payers are planning to file their tax return late, you will need to apply for an extension form before April 15, 2010 or you could have many penalities applied to you along with interest, if you owe taxes.

There are several types of extension forms , considering your type of taxes.

Form 4868  is an application for individual taxes

Form 2350 is  for U S citizens aboard who expect  to qualify for special tax treatment

Form 7004 is an automatic extension of time  to file Corporation income tax return

Form 1138 is an extension form for payment of taxes for corporation expecting a loss

These forms can be down loaded and printed  online using the Adobe Acrobat Reader .