Phil Belanger tells the story behind the name WiFi (and it is not short for "Wireless Fidelity"). Meanwhile, Michael Johas Teener tells the story of where the name FireWire came from. (Scroll down to "Why all these names?")

[9:30am - I originally had a link to a NY Times article, but it was the wrong article and I can't find the right one, so I'm just going to link directly to Michael Jonas Teener's explanation.]