I am a US owner of a i9300 that recently needed warranty service. Here is a guide on how to obtain warranty work and some tips from my experience. I have a feeling we're going to see a surge in people who will need it.
PhoneLand
http://www.freesamsungrepairs.com/
My phone's touchscreen wasn't responding so I contacted PhoneLand in the Bicester area. They asked me to email them my IMEI and serial number to verify that the phone was a EU phone. I guess non-EU phones from places like Dubai or Australia won't work. They got back to me telling me mine was from Germany. After printing out the repair form, I sent it USPS Priority which wasn't the best idea. If sending by USPS, try International Express because it guarantees delivery with a tracking number and you can pay for return shipping also (return shipping saves a lot of trouble and time, trust me on this). It got to the UK in about a week or so. I called them up and confirmed that they received it and they replaced it rather quickly. Paying for return shipping in advance saves a lot trouble because they're not that quick to contact you. I'd say that the whole process took 3 weeks total. I am very satisfied with their warranty service but correspondence with them was difficult because of the time zone difference.
PhoneLand
http://www.freesamsungrepairs.com/
My phone's touchscreen wasn't responding so I contacted PhoneLand in the Bicester area. They asked me to email them my IMEI and serial number to verify that the phone was a EU phone. I guess non-EU phones from places like Dubai or Australia won't work. They got back to me telling me mine was from Germany. After printing out the repair form, I sent it USPS Priority which wasn't the best idea. If sending by USPS, try International Express because it guarantees delivery with a tracking number and you can pay for return shipping also (return shipping saves a lot of trouble and time, trust me on this). It got to the UK in about a week or so. I called them up and confirmed that they received it and they replaced it rather quickly. Paying for return shipping in advance saves a lot trouble because they're not that quick to contact you. I'd say that the whole process took 3 weeks total. I am very satisfied with their warranty service but correspondence with them was difficult because of the time zone difference.