Based on the findings of two freshly uncovered patent applications, Apple is actively exploring internal fans - analogous to those found in laptops and computer towers - for inclusion in future iDevices.
Naturally, such an inclusion of this aforementioned technology would require several significant tweaks over the type of internal fans found in other computers and mobile devices, specifically with regard to the size of the internal fans. Nonetheless, Apple seems interested in giving the iPhone and iPad a mechanism to cool their contained heat.
Here is the abstract description for the mobile device cooling system envisioned by Apple:
A cooling system for a mobile computing device configured to drive two devices, a fan and an alert device. The fan cools components of the mobile computing device by exchanging air between an inner cavity of the mobile computing device and an outer environment surrounding the mobile computing device. The alert device produces an alert, e.g., a vibration, for the mobile computing device. The cooling system includes a motor operably connected to a first device (either the fan or the alert device) and operably connected via a clutch to a second device (either the fan or the alert device). The clutch allows the second device to be selectively activated depending on a speed or rotational direction of a drive shaft of the motor.
Source: USPTO (via AppleInsider)