Will a Unlocked iPhone 4s from US work in Europe?

Yes it will work in Europe. But it must be an unlocked one. But be sure that there won't be any tax for you. otherwise your 4 s will be more expencive than to buy it in Europe

Could you use a larger font, perhaps in bold, as I'm having trouble reading your post.

You'll need to have a GSM iPhone which is officially unlocked, and it is only available at the Apple Store. But remember, that the warranty for an iphone is only valid in the country the phone was bought. So, in case there are some issues with your phone, you'll have to send it back to the USA.

Als have a look at Locating iPhone wireless carriers:

Additional Information

iPhone is available for purchase and activation through Apple, wireless carriers, and authorized resellers (not all options are available in all countries or locations). In most countries, the place of purchase will verify that you have an account with the carrier and then give you instructions on how to activate your iPhone. Verification of carrier account is not required in countries in which unlocked iPhones are available for sale.

Apple Online Store sells unlocked iPhone in the following countries: Australia, Austria, Belgium (French, Dutch),Brazil, Canada (English, French), China, Czech Republic, Denmark, Finland, France, Germany, Czech Republic, Hong Kong (English, Chinese), Hungary, Ireland, Italy, Luxembourg, Malaysia, Mexico, New Zealand, Netherlands, Norway,Poland, Portugal, Singapore, Spain, Sweden, Switzerland (French, German), Taiwan, Thailand, United Arab Emirates,United Kingdom, and United States.

For additional information about iPhone wireless carriers worldwide and where to purchase, select your country.

Look, save youself a lot of grief & purchase an unlocked iPhone in an EU country. At least then you'll have warranty support(valid in all EU countries). If you don't, & purchase in the US, you can then join all the rest of the users who do so & can't get their phones serviced or replaced.

Orange ,Cosmote,Vodafone are all Apple approved

mobile network carriers who will also sell you an iPhone

with a valid warranty most EU country prices are harmonised so unlikely to make savings

by buying outside Romania in another EU country

What do you mean by taxes? And what you sugest me to do?

He means import duties and VAT into EU as iPhone will be shipped in by mail or Courier

and will be picked up by your customs

Doesn't matter who comes to the US & purchases a phone for you...they gonna fly back, to the US, with your phone, if you have ANY issues that involve warranty & support? You won't be able to mail it back. Think & use some common sense here.

Your uncle will probably be legally obligated to declare that he purchased the iPhone outside your country and may be liable for import duties. Consult your government's information in import of goods. I'd strongly suggest not trying to "sneak" something into the country; the fines and other penalties involved often are severe.

Most states and cities in the US also charge sales taxes, and there's no way to get around having to pay those, so yes, you will have to pay some tax. Those sales taxes are not reflected in the prices you see quoted on Apple's web site.

Regards.

But no warranty iPhone will have to be returned to US for any warranty faults

However if you are determined

ensure the iPhone is

Unlocked NOT CONTRACT FREE ( which IS locked and same price )

Unlocked are ONLY available from Apple Retail Stores or Apple.com

suggest he uses Apple .com online store that will be an unlocked iPhone

and that the iPhone is GSM

Smart move.