Want to use the "official" phonetic alphabet when you spell a part number or serial number over the phone? Here is the current NATO phonetic alphabet:

Alpha
Bravo
Charlie
Delta
Echo
Foxtrot
Golf
Hotel
India
Juliet
Kilo
Lima
Mike
November
Oscar
Papa
Quebec
Romeo
Sierra
Tango
Uniform
Victor
Whisky
X-Ray
Yankee
Zulu

Older phonetic alphabets used Able, Baker, Charlie, Dog, Easy, etc. Amateur radio operators sometimes change the letters up to make them easier to remember or say; the letters M-M in a call sign, instead of "Mike-Mike" could be "Mickey Mouse."

Although your coolness factor goes up if you use the correct letters, you can use anything you want as long as it's easily understandable.