Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
Wireless cards can be quite a bit of trouble for Linux users. Very few manufacturers have any interest in writing Linux drivers or releasing information about their cards so other people can use this information to write Linux drivers. There is a small selection of Linux-compatible Wi-Fi (wireless networking) cards, but they tend to be rather expensive. Worse, you don't get very much choice about which wireless networking chipset is built-in when you buy a laptop.
ndiswrapper is a project that provides a kernel module to load Windows NDIS wireless card drivers under Linux. NDIS stands for Network Driver Interface Specification and is the Windows/DOS driver interface. The ndiswrapper module wraps around this driver, acting as a translator between it and the Linux kernel.
You can use ndiswrapper to get a great deal of cards working that don't have a native Linux driver.