Ok well it’s not really called the iCupholder, but it’s pretty much what it is. Apple has recently patented a device similar to Belkin’s TuneDok Car Holder for iPod, in which Apple described it as being:
An “apparatus that can secure an electronic device and be inserted into a conventional cup holder. The cup holder, for example, is inside of an automobile."
Similar to Belkin's (US)$30 TuneDok, the Apple iPod dock employs adapting sleeves that fit around the base of the apparatus and can be used to adapt the device holder to cup holders of different sizes and shapes.
The base of the unit -- the part which gets inserted into the cup-holder -- includes a winding spool for managing the cable used to connect the iPod to an automobile's audio system. By contrast, the TuneDok uses a "desecrate cable-management clip.”