I have recently acquired The History of Alexander, bu Rufus.
  It talks about one of the first battles between Alexander's army and the army of Darius III of Persia.
  Darius army had 6000 slingers and archers in front of it.
  It doesn't say how many slingers Alexander had.
The ironic part about is that most of the slingers in Darius's army were Greek mercenarys

alexander wasn't greek - he was macedonian. Even today macedonians object to being called greek.
In fact the term 'Greek' is relatively new. The country was divided into city states and your allegiance and nationality was first to your city state and second - if at all - to those who spoke the same language (about the only common connection).

uhm... he slung an lead glande high up in the air and cought it with his eye?

Strange cooincidence... I found the following web site a week or so ago. Rather boringly it claims that the injury was due to an arrow at the seige of Methone. However I hadn't realised that Phillip's body had been found - maybe...

     http://www.rn-ds-partnership.com/reconstruction/phillip.html

There were no "Greeks" at this time, but Athenians, Corinthians, Spartans etc, who disliked each other heartily. It was only in times of great need (such as during the Persian wars) that they forgot their hostilities and worked together. It was Alexander who laid the groundwork for a Hellenic identity.

A rejoinder, two years later, from a professional Classicist (and keen but bad recreational slinger)

-- There was a clear concept, by the Classical period, of "the Greeks". The word is not in Homer (only "Achaians" and "Argives"), but Archilochos (ca. 630 BC) already mentions "the dregs of all the Greeks". At the end of Herodotos Book 8, there is a definition of "the Greeks": those who speak the same language, worship the same gods, share the same customs. In Herodotos, 4, the Skythian king Skyles is said to go to a Greek city and indulge in the Greek lifestyle, away from his subjects. On all this, see M. I Finley's essay on Greek identity (which did not need a nation-state to express itself); or the recent work by Jonathan Hall. The alliance of 480 aganst the Persian was called the Greek alliance; in 432, the Spartans voted to go to war "to free the Greeks", etc. Greek consciousness quite compatible with squabbling among Greek city-states (often with persian money: for instance, the Spartans took persian money, in 407 BC and also in 392 BC: D. Lewis, Sparta and Persia).

-- The Macedonians probably did speak Greek (O. Masson, in Oxford Classical Dictionary, third edition), but with a different pronunciation; they did worship the same gods as the Southern Greeks; they have a place in the  Greek mythological and legendary landscape (an eopnymous hero turns up in a fragment of Hesiod). They should probably be called Greek; with the proviso that Athenians did call them non-Greek, and that they had a strong regional identity that set them apart from southern Greeks. The modern citizens of the post-Yugoslav nation state, whose capital is Skopje (Republic of Macedonia, or Former Yugoslav Republic of Macedonia), are not the descendants of the ancient Macedonians, but Slavic-speaking descendants of populations who moved into the northern area of historical Macedonia in the seventh century BC, with a national identity which emerged in late Ottoman times.

-- lead sling bullets: apart from the Cypriot early Iron age examples (Hala Sultan Tekke), the earliest mention is indeed Xenophon Anabasis 3.18 (I think), for Rhodians; the earliest securely dated example is probably the sling bullet in the name of the Persian satrap Tissaphernes (C. Foss, Journal of Hellenic Studies 1975), then various mid C4th ones (including the famous Olynthos ones, to which add those found at Stageira and Poteidatai, now in Polygiros museum). Note that Tracey Rihll, The Catapult (2007), 104-7, argues that ALL lead bullets are made for the catapult-- which I think excessive.

I hope this is useful

Yes, the Xen passage is rather a problem, and the Tissaphernes bullet. I believe she has a lot of arguments that may indicate that at least some glandes where used by catapults (and Appian, Mithridatica, explicitlymentions them used by catapults during the siege of Athens). Acerbic review of Rihll on ajaonline.org

www.ajaonline.org/pdfs/book_reviews/112.1/04_Campbell.pdf

I must admit I haven't read Rihll, only gotten a summary from a colleague. Also there quite a lot of stuff (I hear) on sling velocities (pp. 101-2, or so I'm told)

Thearos wrote on Feb 28^th, 2009 at 8:36pm:

Given the evidence, it seems indefensible.

I have read some of the reviews with interest, and I can't decide whether this is a worthwhile book or not.

Does anyone here have a copy, or any further opinions on it? I see several reviewers compare it with Marsden's "Greek and Roman Artillery", but one of them seeths that the physics side of her discussions are "nonsense".