The internal wireless card is an Intel Wireless WiFi Link 5100. The driver used by default is iwlagn. There is mention of iwlwifi being good for injection.

But injection works, to some not-clearly-understood-by-me extent, with the default drivers.

From Jay Scott:

wget http://www.orbit-lab.org/kernel/compat-wireless-2.6-stable/v2.6.37/compat-wireless-2.6.37-4.tar.bz2
tar -xvjf compat-wireless-2.6.37-4.tar.bz2
cd compat-wireless-2.6.37-4
wget http://patches.aircrack-ng.org/channel-negative-one-maxim.patch
patch  p1 < channel-negative-one-maxim.patch
make
make install
make unload