The smart phone industry as a whole is a unique one in that most often competitors are also partners. In the case of Samsung and Apple, on a commercial level they each have their own line of smart phones aimed at consumers. They also compete on technology levels and are currently in several litigations around patent infringement and other legal issues. It's amazing to see that despite all the issues between the two companies, they can continue to do business with each other.
In addition to being competitors, Samsung and Apple are also partners on several levels. Much of the inner workings of an unlocked iPhone are components manufactured by the major mobile companies in the world including Samsung, LG, and others.
A recent news release is speculating that the Samsung Quad-Core A6 Chip will be the processor of choice used in the next iPhone release scheduled for the summer of 2012. Apparently Apple is inquiring about the availability of the chip and the timeline in which they can secure them in preparation for the next version of their phone. This is perhaps another indication of how well Samsung is doing in the development of technology area of the industry. For their main competitor of the unlocked Samsung Galaxy S II, Apple to decide to use Samsung as their main chip provider shows that they are a leader in the space.
As the year round off and the data starts to come in terms of sales, it is believed that Apple will be Samsungs biggest overseas client accounting for over 8 billion in sales of its components including liquid crystal displays and memory chips. As a news release I'm sure Apple wishes this type information was not made public as it only boosts the Samsung brand and puts them more to the forefront in terms of being a serious competitor to Apple.