A flash card reader allows you to read from (and write to) your flash card via your PC or Mac.
They come in different shapes and sizes. The cheaper ones usually accommodate only one type of card. As the price increases the capability to access more of the different types of flash card available also increases.
For example, if you only wish to access your photos from your Compact Flash card, a dedicated Compact Flash card reader will do for a few pounds.
If you need to access different types of cards some of the more expensive readers can accept Secure Digital, MMC, Memory Sticks, xD and so on, as well as Compact Flash cards.
Readers either connect via a USB or FireWire port on your computer. You must check which you require.
Some high-end readers are required for the latest fastest cards, such as the SDHC cards and Extreme IV Compact Flash.
The smaller readers can resemble a USB pen drive, with slots on the side for your card(s). While other readers are designed to be desk mounted and connected to your computer via a supplied cable.
As memory card technology gets better, it is important to update your card reader also.
Some readers cannot be used with laptops, such as the very high speed firewire readers. The Firewire ports on laptops do not have the power supply capacity to power these readers.