credit to JoshuaJSlone for all of this:

http://www.neogaf.com/forum/showthread.php?t=99587

http://press.nintendo.com/e32k6/News/ADI-Nintendo_PR_2006-5-8Approved.pdf

http://www.analog.com/en/prod/0,2877,ADXL330,00.html
It looks like on that page they can be purchased in bulk (1000-4999)
for $5.45 apiece

The ADXL330 is a small, low power (200µA at 2V) 3-axis iMEMS®
accelerometer complete with signal conditioned voltage outputs on a
single monolithic IC. The product measures acceleration with a minimum
full-scale range of ±3g. For tilt sensing applications it measures the
static acceleration of gravity. It also measures dynamic acceleration
resulting from motion, shock, or vibration. The ADXL330 is available in
a small 4 mm × 4 mm × 1.45 mm, 16-lead, plastic LFCSP.

* Applications: Motion and Tilt sensing in Mobile Devices
* Handsets
* Motion-Enabled Gaming Devices
* Disk Drive Protection Systems
* Sports and Health Devices

Here's an article from late last year about the ADXL330.
http://www.edn.com/article/CA6280420.html?ref=nbsa

most interesting Wii-related bits

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"This is the first three-axis motion sensor accelerometer...and the
first single-chip three-axis MEMS accelerometer with signal
conditioning and circuitry together on the same chip," said Mack Lund,
the company's product marketing manager for micromachined products. The
chip's mechanical sensing structures allow it to offer low power in a
small package while also providing stable performance over its
temperature range, he said.

In addition, the device's low supply voltage, from 2.0 to 3.6V,
benefits battery-powered applications, Lund said. "If users only need
to use this for short periods of time or they want to duty-cycle it,
they can get even lower power than best-in-class," he said. The device
can turn on in 1 msec, take a measurement, and turn off again to save
power, he said.

...

The ADXL330 is now sampling and costs less than $2 in high volume,
according to the company. It is slated for volume production during the
first quarter of next year.
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