Apple has hired a new executive into its Display group - Dr. Jueng Jil Lee, a former OLED research fellow at LG Display, who apparently was involved with printing technology research. Dr. Lee's previous employee (before LGD) was Cambridge Display Technology, the P-OLED pioneer (now owned by Sumitomo).
Apple is interested in OLEDs, and the company already has several patents involving flexible OLEDs, OLED based BLUs for LCDs, OLED control schemes and others. Rumors about OLED products from Apple keep coming (the latest one involving 50" bendable TVs is rather dubious). I guess an OLED iOS product will come eventually - the real question is when...
Source: The OLED-A