It is little coincidence that the people who sell rechargeable batteries advertises on digicam web sites. They know who their market is. There are a few ways of doing this. The slowest is with a serial cable. Newer cameras have USB ports that are nice and fast and most newer PCs and laptops have a USB port too.
Card readers are available that fit into a variety of ports and read a variety of cards.
This works well. Get your camera first then get the card reader that works with the media your camera uses and the port your PC has open. Some cameras are giving away free card readers rather than putting USB ports on their cameras. There is a little quirk with these you need to know. The files are compressed.