Hi All,
I want to ask to Tax file extension for this year. How is it going to affect the I864? Will they accept my W2 only for this year plus my last 3 years or they want this year filed tax too

I don't know if it is sufficient or not, but I sent a copy of my 2007 w2 to my wife for the interview.
I wont have my taxes done until later, so it is all I have for now.

Seems like if they want to prove income, the w2 would be enough.. but who really knows

From the I-864 - Item 25, page 8:

You must provide either an IRS transcript or a photocopy from your own records of your Federal individual income tax return for the most recent tax year. If you believe additional returns may help you to establish your ability to maintain sufficient income, you may submit transcripts or photocopies of your Federal individual income tax returns for the three most recent years.

From USCIS:

The sponsor must submit with the Form I-864 the sponsor’s U.S. Federal income tax return for the most recent tax year (that is, the completed tax year immediately preceding the date the sponsor signs the Form I-864). USCIS may generally expect a sponsor, after April 15 of any given year (or April 16 or 17, in a year in which April 15 is on a Saturday or Sunday), to have completed his or her tax return for the previous year. If the sponsor requested an extension, the sponsor should provide proof of filing for the extension. If the sponsor did not file a tax return, the sponsor must prove that he or she was not required to file. If a sponsor should have filed, the sponsor must file retroactively and provide proof of filing. Note that U.S. citizens generally have an obligation to file a tax return on non-U.S. earnings even if there was no tax liability.

in most cases it not alway true that u have to submit your current tax return.
what they looking at the ability for you to support your sponsor and not become
a public burden when he/she come over here.

tax return is needed but not alway
you can submit w2 bank statement to prove you have enough income

Just take what you have. And, if asked, tell them you extended the 2007 tax return. If it's before the deadlines (April 15, June 15, or October 15) you are fine.

A question for you Sharif
you don't have to answer if you don't want to
why did you file the extension?
if you think you gonna owe the tax and can not pay right away, you have the option to pay in monthly installments with low interest rate

Not this or that) my wife lives in Iraq and she cannot get me a certified passport copy. If I would file without that then I will owe money If I wait until she go to her interview hopefully in few months then she can do it and I don’t need to pay anything

As long as your interview is brfore 4-15, the 2006 return would be the current TR. If after, your w-2 and current pay check stubs should be enough proof, and they may ask for these prior to 4-15.

As for the extension, which I am also going to use, just make sure you have paid in enouch so that you won't owe anything, and when you do file, attach a letter signed by both of you stating that you wish your spouse to be treated as a resident alien for tax purposes for the entire year of 2007.