The timeline related to when the genus homo used spears has been recently elucidated. Human ancestors were killing game about 3/4 of a million years ago in the Middle East, as evidenced by butchered deer carcasses. Until now, the earliest stone spear tips were found at a Neandertal site in France and dated from 300 to 200 thousand years ago. Wooden spears have been found among the remains of butchered horses in Germany and dated to 400,000 years ago.
Researchers in South Africa have now unearthed stone spear tips made by a common ancestor of Neandertals and Homo sapiens around 500,000 years ago. The spears were either thrusting spears or thrown at close range. The time frame was determined using soil analysis in which the spear tips were buried, a common dating technique. [Recently stone arrow tips have been dated to 71,000 years ago, which pushes back these hunting tools by several thousand years.]
The stone spear tips were made from silcrete [see http://en.wikipedia.org/wiki/Silcrete] that were heated to make the stone easier to chip. The tips were found among sediments spanning a period of 11,000 years. Two fascinating conclusions flow from these facts. First, it shows that complicated instructions for building multipart tools could be passed over hundreds of generations. Second, it shows that Neandertals and Homo sapiens shared, through a common ancestor, whatever mental abilities were needed for hafted stone-tool technology [stone tools with a handle or hilt].
It was not until much later that Stone Age humans learned to make devices like spear-throwers that could hurl spears farther, harder, and more accurately. [Since Neandertals apparently did not develop such technology, it is thought by some researchers that this gave Homo sapiens a significant survival advantage, and may explain(at least in part) the demise of Neandertals, especially as climate change decreased the forested areas in which their thrusting-spear strategy for hunting was effective.]
Research reports on this topic can be found at: http://www.nature.com/nature/journal/v491/n7425/full/nature11660.html; http://www.sciencemag.org/content/338/6109/942.abstract.