MacRumors has come across an Apple job listing for someone with:

excellent understanding and knowledge of processor architecture, specifically ARM and its vector unit NEON. Additional Intel SSE or PowerPC AltiVec is also very helpful. Being able to use processor micro-architecture to write and deliver fast routines is an essential attribute.

Neon, they remind us, is the brand name for the ARMv7 Cortex, the next-generation of the processor Apple uses in the current iPhone and iPod touch.

What's not yet clear is whether Apple will tap the multi-core potential of the ARMv7 Cortex to really shift multimedia performance into the mobile stratosphere. However, another tantalizing glimpse into the iPhone's potential future is revealed in a second job listing, this one for an engineer with:

Experience developing embedded image and video processing solutions. Experience developing embedded image and video analysis solutions. Experience working on real-time media and networking applications (WiFi and cellular networks).

Of course, we won't keep our fingers crossed too hard for those iTunes Replay, personalized podcast streaming, or remote DVR access patents Apple has teases us with in the past...