Hello everyone! In my research for taxation found this forum which I think is great to socialize with expats especially here in Greece. So besides my tax question I will read the forum regularly, nice job!

I obtained through my mother my US citizenship this year 2012. l live and work for the greek goverment and pay taxes here.

What actions should I take with the IRS of USA? Do I owe taxes from the past when I didnt have the citizenship. I want to be good tax wise if I decide to go and live in the US with my greek wife in the future.

Sry for my english, born and raised in Greece

If you've only just obtained your US citizenship this year, the first thing to do is to apply for a US Social Security number (because, without that, you can't file tax returns). The website for the US consulate in Athens should have information about how to do this - possibly under the heading of "federal benefits" if they don't have a "social security" section.

Don't open the issue of prior tax obligations. Just assume that your obligation to file begins from the date your citizenship papers came into force - if the IRS thinks differently, they'll be in touch. You won't file anything until the first few months of 2013 - filings are due June 15th for those living outside the US.
Cheers,
Bev

Yeah, because I applied for the citizenship in Florida, I updated all my info at the SSA and obtained a FL drivers licence.

Do you think that I will be able to file my taxes through the internet, or the procedure will be too mixed up, and I should hire an accountant back in the US?

E-filing for expats can be a real can of worms. You can generally use most of the online tax preparation software, but when it comes to actually filing, many require you to pay their service fee (or pay to file a state return, which you shouldn't have to file if you're not resident in any US state).

Each year there is a list of free online filing services, but only about 6 or 8 can deal with foreign addresses. (NOT worth it to maintain a US filing address, since this just calls into question your use of the FEIE for your salary income.) Of the 6 or 8 that will allow overseas taxpayers to e-file for free, they all have age, income and other restrictions. If you fall within their parameters, you can e-file for free. If not, the cheapest e-filer charges less than $10 (or did this past year).
Cheers,
Bev

Florida is a good choice! I moved my voting base to Florida too and highly recommend that all American expats do the same. Getting 6 million expats to be registered voters in Florida is the only way that we'll ever get any political representation. Until then, your vote is absolutely worthless.

Over the years, I've been playing with various free e-filers. Some will allow you to file if you invent a magical income of $1. Others are too heavily anti-citizenship-based taxation to allow one to file form 2555 or accept a foreign address.

Freefile is probably the best choice since it might be the least likely to tell one that they can't file even though they are told that they are supposed to.

If you're referring to Free File fillable forms, you might want to note the following caveat right on the first page of the site:

Cheers,
Bev

Oh, I maybe I used a US address then or gave up after trying. I'll try this one again next year, blog it and report any issues with the IRS, assuming that I'll still be a US citizen then.

If Americans abroad cannot use Free File fillable forms, then the IRS needs apologize to the American people and financially compensate us for each year that this problem is not fixed. One simply cannot advocate citizenship taxation and tell people that they must file while denying them the ability to file simply because they don't live in the US. Shoot me for being honest, but this is insane and the US government owes us an apology for taxing us without representation.

Update: I decided to go to Florida and live. As I mentioned before, I obtained the US citizenship this year. When should I file my taxes of 2012, where all my income was earned and taxed in Greece? I will have to file in Greece also at least for the last time, but things are complicated when starting in the US.

You will have till around the 15th of June to file. Approx. $95,100 of your income might be excluded from taxation since you lived in Greece, along with maybe around another $30k for housing. You might be able to free file online. I did a review on that here:

Myth: EVERYONE is Eligible to Free File! | American Working Middle Class Abroad

If you're living in the US, then you will have until April 15th, 2013 to file your 2012 returns, not June 15th. (The June deadline is for those resident overseas on the April 15th deadline.) You'll have to report your worldwide income for the full 2012 calendar year - and then either apply the FEIE (earned income exclusion) to the salary income earned while you were resident in Greece or apply the Greek income taxes paid against your US income tax liability so that you're not paying twice. (Honestly, even if Greek taxes are higher, the FEIE is usually the easier way to go by a long shot.)
Cheers,
Bev