http://www.post-gazette.com/pg/06060/662669.stm

In addition to the cell phones issue the study says...

QUOTE
Airlines typically allow the use of portable electronic devices, like game
players and DVDs, above 10,000 feet, but not during takeoff or landing.
Laptops also can be used, but not for communications purposes, such as
sending or receiving e-mail.

In the past, the FAA has found nothing to indicate that the use of passive
devices like laptops or game-playing electronics poses a threat to the
aircraft.

However, the CMU study concluded otherwise. While the researchers looked
primarily at cell phone use, they also discovered that emissions from other
portable devices proved "problematic."

"We found that the risk posed by these portable devices is higher than
previously believed," researcher Bill Strauss said in a release announcing
the findings.

/QUOTE

I also liked this little tidbit...

QUOTE

And despite the ban on cell phone use during flights, the researchers
discovered that on average one to four cell phone calls are made from every
commercial flight in the northeast United States.

Some are even made during critical flight times, such as the climb after
takeoff or the final approach.

/QUOTE