Compact flash devices generally pretend to be DOS formatted hard disks. Accessing them is just a matter of applying the correct software to the right hardware adaptor. There are PC Card readers, which fit into laptops, and can be purchased as PCI cards for desktops, and there are USB card readers both external and internal for PCs and desktop machines.
The great advantage of card readers is speed. Even an old pcmcia card reader is several times faster than the average CF. The computing overhead is also low and I get good performance from a 75MHz laptop with 24 MB of RAM. USB card readers are also faster than the average camera as they can be USB 2 and lack client overhead. Regular USB seems plodding by comparison and can even deplete your camera's battery!
The other big advantage is the ability to use any software you want to browse the images. Gqview works very well on my laptop when I travel and sftp through Konqueror is an excellent browser when I'm home.
I've been using a Compact Flash (CF) PC Card adaptor on my laptop to get images from my and my wife's cameras for years now. When you put the card in, the kernel sees it as a hard drive and it is noted in your log files, specifically, /var/log/messages. A typical entry looks like this:
Jun 12 19:00:40 old76 kernel: ide_cs: hde: Vcc = 5.0, Vpp = 0.0
Jun 12 19:18:15 old76 kernel: hde: TOSHIBA THNCF064MAA, ATA DISK drive
Jun 12 19:18:15 old76 kernel: hde: 125184 sectors (64 MB) w/2KiB Cache, CHS=978/4/32
Mounting the device is as easy as typing "mount /dev/hde1 /mnt -t msdos" as root. I've made a GUI mounter in KDE, but the mount command is still easier for me. Newer distributions would use Kmount or similar.
My little brother set up a USB card reader under Fedora and had no problems. He used it to read Sony memory sticks.