In the iTunes Store you can buy songs, podcasts, movies or TV series in HD quality and then download it to your iPod or iPhone. You can also get new Apps, games and even lessons from universities.
Online Gold mediates iTunes Gift Cards with credits of 10, 15, 25 or 50 dollars. The Cards can only be redeemed in the US iTunes Store. If you are not resident of the United States you just have to open your iTunes, open the store, go down to the bottom of the page and then click the flag in the right corner to change the country. Now you can redeem your iTunes Gift Card without any problems.
You will receive the code of your iTunes Gift Card via email within 5-10 minutes after receipt of payment. Thus you won't lose time and will be able to use the iTunes Gift Card immediately.
Watch this video tutorial how to create a US iTunes Account, if you don't know how to do it: