Delays are a Nintendo fan's only constant.
Yomiuri Online reported recently that Nintendo may have trouble realising the Gameboy Advance's proposed August release in Japan. They reported that shortages in semiconductor parts in the manufacturing process of the next-generation handheld could be the prime reason. Other factors that may contribute to the delay could be the recent hold-up of the network adaptor for the Gameboy Color being pushed back untill fall instead of being released this month in Japan. "This may also affect the release of the company's next-generation console system Dolphin, in Japan as well. Nintendo may find it unnecessary to release its next-generation hardware yet, since its current hardware are still selling pretty well." It all seems reasonable as financially Nintendo really do not need to push for a quick release of either the GBA or Dolphin, because business is currently very good for the Big N.