Daylight savings time was first proposed by Benjamin Franklin during his tenure as the American minister to France in 1784. Franklin noted that the sun came up long before the residents of Paris awoke, yet it went down long before they finished their daily activities. Franklin calculated that 64 million pounds of candle wax was being unnecessarily burnt which equated to 96 million livres tournois (the equivalent of around $200 million today). Things did not change for more than 100 years until in 1907 a builder and fellow of the Royal Astronomical Society, William Willett, printed a pamphlet "The Waste Of Daylight" outlining the savings to the UK economy if the clocks were to be advanced in the Summer months. A Daylight Savings Bill was introduced to the UK parliament in 1908 but was defeated. It wasn't until the onset of the First World War and the need to economise that the UK accepted the need to have DST and introduced it in the Summer Time Act of 1916 (but not before the Kaiser had introduced it across Germany and Austria).
There are no set rules across the World as to when and where DST is implemented, it is left for each country (or region) to decide whether or not to implement it and when that should be. Generally (and this is a very broad generalisation) DST is more likely to be applied the further from the equator (North or South) you travel. The usual amount of change is +1 hour.
For further information on DST:
Prerau, D [2005], "Saving The Daylight", Granta Books, ISBN 978-1-86207-878-9
Willett, W [1907], "The Waste of Daylight". available to view - http://webexhibits.org/daylightsaving/willett.html