Answered this for a friend, thought I'd post it here, I was suprised there were 10. BTW, some of these are very lame, I'm not suggesting that they are all practical. This is for TWO computers; if you have more than 2, or if you also want to get to the Internet, things change and some of the options fall out.
- - to Stacey - -
1: Network port to network port, with a SPECIAL cable, a "cross-over Ethernet cable", *usually* red or orange, but color is no guarantee of wiring (special cable not needed on VERY new computers with Gigabit, but I doubt you have that)
2: Network port to network port with 2 regular Ethernet cables and a hub or switch (a box)
3: Wifi to Wifi in "peer" mode, but does not use security/encryption. Extreme Nerds could also setup a non-peer client-server mode, which would be secure, but beyond my normal realm of nerdy-ness.
4: USB to USB with a SPECIAL cable, has the same USB plug on both ends AND a small fat oval plastic puck in the middle of the cable, this is sometimes called a "USB laplink cable" or a "USB to USB networking cable
5: Firewire to Firewire with a **generic** Firewire cable. If you have a cable with the proper plugs that will plug into both PCs (or pc and mac) it will probably work
Oh and what the heck....
6: On old computers, you could use a null-modem SERIAL cable (RS232 null modem / patch cable / cross over cable)
7: If you have 2 phone lines, you can go modem to modem
8: If both laptops have an IR port (infrared port), you can sometimes network that way.
9: You may be able use Bluetooth to bluetooth, though I haven't done that
10: And of course "sneaker net", with CDs, floppies, or a USB Thumb Drive