Apple has allegedly already switched away from Samsung for production of the next-gen A6 processor for iOS devices, and if the latest report from Digitimes is accurate, Apple's also diversifying its sources for DRAM and NAND memory. Digitimes' sources claim that Apple is now starting to source NAND memory from Toshiba and mobile RAM from Elpida.
Currently, a fairly large proportion of the internal components of iPhones and iPads are actually manufactured by Samsung. Considering the much-publicized global patent spats between the two companies, this puts Apple in a potentially awkward position. It makes good business sense for Apple to start sourcing components from the few tech companies on Earth that haven't filed lawsuits against it (yet).
MacRumors points out that Samsung's currently contracted for US$7.8 billion in parts over 2011, including the A5 processor that powers the iPad 2. Although Samsung is the world's largest supplier of many electronic components, losing Apple's business will likely put a very large dent in the Korean tech giant's ledger.