Guidelines for Names(taken from MSDN)

Cast Style

Pascal Casting : First letter in the identifier and the first letter of each subsequent concatenated word are capitalize.Use Pascal case for identifiers for three or more characters .

E.g: BlackColor

Camel Casting : first letter of identifier is lowercase and first letter of each subsequent concatenated word is capitalize

E.g: blackColor

UpperCase :All the letters in the identifiers are capitalized.

E.g : IO

For more details MSDN