Reader drives for your PC
There are several ways of transferring the images from a digital camera to the PC: either by connecting the camera directly to the PC via USB and downloading the images (more on this in the connectivity section below), or by using a memory card reader.
There are a range of memory card readers now available in the market, and they are priced very competitively. A five-in-one card reader that supports all the major formats can be bought for as little as $30.
Select vendors have also taken image downloading a step farther, and released printers which allow you simply to hook your digital camera directly to the printer to print images, bypassing the PC. Some now also contain built-in multiple memory card readers, so you can print your images directly from your memory card, as well as perform basic image manipulation on the device's LCD screen.
Connectivity
The standard your camera uses to transfer data requires your PC to have the relevant ports. How fast data transfer is will depend on these and your camera's connection standard.
Universal Serial Bus
The vast majority of digital cameras on the market use Universal Serial Bus (USB) to connect to a PC. USB allows easy installation of peripheral devices; just connect your camera to its cable and the cable to your PC. You don't have to install device drivers or even turn off your PC.
These days, pretty much every camera contains a USB 2.0 port, which runs at 480Mbps. This is considerably faster than the 12Mbs USB 1.1 ports that used to be used. Keep in mind though, to make proper use of US 2.0 your computer will have to support the interface, which many older machines do not. Otherwise you'll be forced to transfer at USB 1.1 speeds.
FireWire
FireWire, also known as IEEE 1394, transfers data at the same speed as USB 2.0, but is more commonly used by digital video cameras to transfer video. There are a few high end D-SLRs that have this connection, but for the most part you won't find it on any sort of consumer camera.
An advantage of FireWire is that it allows some cameras to receive power from the connection. Therefore, you could connect your unpowered camera with a FireWire connection and receive power from the bus.
Another benefit is that FireWire uses peer to peer connections, letting you transfer data between FireWire devices without a PC. USB is host-based, requiring a connection to a PC. Peer to peer connections are useful if you want to move photos from one camera to another, or perhaps from a camera to a digital video camera.