PascalCasing and camelCasing

PascalCasing is where the first letter of each word is in upper case. It's the same with ucwords in php. This is usually used in naming a class.

MyHelloWorld
JoomlaComponent

camelCasing is where the first letter of the first word is in lowercase while the first letter of the subsequent words are in uppercase. It's the same with ucwords in php except that the first letter is in lowercase. This is usually used in naming a function or variables.

myHelloWorld
joomlaComponent