There's some generally accepted phonetics that are used - NATO (Alpha, Bravo, Charlie, Delta, Echo, Foxtrot, etc.), Financial (Adam, Bob, Carol, David, Frank), and LAPD (Adam, Boy, Charles, David, Frank).
But my favorite has got to be civilian phonetics.
A as in ahhhhhh!
B as in bubbles
C as in Chattanooga
D as in deluge
E as in echocardiogram
F as in F**K
G as in "gurassic" (I think they meant Jurassic)
H as in hedgehog
I as in... "I dunno"
J as in "just get here now"
K as in kleptomaniac
L as in loser
M as in murder
N as in nope
O as in "oh heeeeellllllllllll naw"
P as in penis. Yes. This has been said.
Q as in "the letter no one uses"
R as in "errrrrrrrrrr"
S as in shit
T as in telefono
U as in unicorn
V as in "very, very, very...extraordinary..." (And yes - this was sung to me)
W as in "well..."
X as in Xavier
Y as in yelling
Z as in "sleeping"
and so, so many more. What crazy phonetics have you heard?