There are clear linkages between Sumeria and Syria and into northern Arabia. The Allah thing worshipped by Moslems today is an obvious manifestation of the Sumerian moon cult. The Sumerian empire transferred the worship of a Baal moon idol far and wide throughout the Near East. Most historians believe that that the Arabian Allah originated in Syria, via Sumeria. The Aramaeans inhabited Syria around 1300 BC and were greatly influenced by the astral cult of Sumer. The principal deities,were the storm-god Hadad; the sky-god Alaha and the goddess Athargatis. The Syrians obtained the Allah figure from the Sumer city of Babylon. Babylon would inherit the Sumerian empire and reach an apogee under Nebuchadnezzar in the late 6^th century BC. Babylonian influence would range far and wide and include the Arabian peninsula. Even the idea of worshipping a black rock as a divine object of power originated in Syria:

According to Arab historians, Petra (north Arabia, close to Syria, the home of the Nabateans), had a kind of Ka'ba with Dushara (Dusares), worshipped under the form of a black rectangular stone, at the head of the pantheon [Hitti, 2002, p. 72].

The Allah thing was named Alaha in Syria [see Walker, 2004, p. 20]. Allah was a male God, the supreme God, the one associated with Ba'al or Hub'Al [Hub'Allah]; all of whom had three daughters, Allat, Uzza and Manat. The Nabateans, who were in Jewish lore were apparently the first-born sons of Ismail in the Sinai Peninsula, were the first to bring this Allah idol to Arabia from Syria [ibid., p. 22]. Allah had a few names in fact the Koran lists 99. most likely the semitic Nabateans used words such as:Elh and Alh to denote the Allah or key Lord [Sin in Babylonian]. Along with the Allah, the Nabateans also brought the veneration of Hub'Al, a male idol who was the 'main Lord' in their pantheon. This Hubal was later placed in the precinct of Ka'ba and became the greatest of the pagan Arab idols

Hub'Al [lah] was represented in the form of a massive anthropomorphic statue, perhaps made of red agnate stone. Historians and archeologists believe that his right hand might have been broken off [on purpose or to represent something important?]. Muhammad's tribe the Quraysh or Quraish, worshipped Hub'Al in this form and made for it a hand of gold. The Hub'Al idol stood in front of the Ka'ba signifying its importance and pre-eminence.

Hub'Al worship informed the cultural artefacts of Quraish existence. Festivals, rituals, burials, sex fertility orgies, markets and even divination arrows to determine the legitimacy of a newly born child [Al-Kalbi, 1952, p. 23] we a part of the Hub'Al's veneration. Most historians agree that this Hub'Al was the physical representation of the 'ilah' or the main 'one Lord' or Allah at the Ka'ba. In his youth Muhammad helped of course with the ritualistic preparations which were mandatory to appease the Lord high god Hub'Al. [Walker, 2004, p. 42]. Muhammad's grandfather was the keeper of the Hub'Al shrine and his father was named after Hub'Al [Abdullah or slave of Allah].

Even Muhammad's hagiographer, Martin Lings, a Catholic convert to Islam, agrees that Hub'Al and Al'Lah worship came from Syria [Lings, 1983, p. 5, 11]. Arab Historians also confirm that the mighty Hub'Al – Zeus like in his dominance and power -- was actually an ancient variation of the Babylonian 'Sin' or 'Allah' meaning the 'one'. The word Hub'Al is derived from the Semitic word Hu,which means 'He' or 'He is' with the suffix El, which, of course, is another name for Allah. Al is also used in place of El. Hub'Al was the great protector of Mecca, the fearsome god who fought against 'his' enemies. Hub'Al was ceremoniously invoked by the Quraysh during battle as a war cry for example, and was credited with saving Mecca from the Ethiopian invasion of 571 AD.

Long before the time of Muhammad the concept of this moon idol Allah, had spread all over the arid Arabian peninsula. An inscription found in south Arabia bears the name of Allah. Allah is Hallah in this Safa inscription written some five centuries before Islam. Another name for this Allah was Wadd-the moon god which stood at the head of the Minaean Pantheon. Allat, Uzza and Manat were the three daughters of Allah for this Wadd [see the Arab and Moslem apologist Hitti, 2002, pp. 97-98]. 

There is little dispute that Allah is a Sumerian-Babylonian astral object. The Koran lists 99 names for this thing Allah. Here is a partial list of the Allah names and places:

The Sumerian Allah: (Sumer, Babylon; and then Mecca).
The Alaha Allah: (Syria, then Mecca).
The Elh Allah: (Syria, then Mecca).
The Ilah Allah: (Syria, then Mecca).
Sin Allah: (Hadramawt, then Mecca).
Ilu Allah: (Babylon, Syria and then Mecca).
Hallah Allah: (Syria, then Mecca).
The Hubal Allah: (Syria, then Ka'ba, Mecca).

The moon Allah: (south Arabia, then Mecca).
The sun Allah (Baal): (Egypt, then probably Mecca).
The Jehovah Allah: (probably, Palestine, then Mecca).
Elohim Allah: (central Arabia, then Mecca).
Ila Allah : (central Arabia, then Mecca).
The ar-Rahman Allah: (north Arabia, south Arabia, then Mecca).
The ar-Rahim Allah: (Yemen, then Mecca).

El Allah: (Palestine, then Mecca).
Wadd Allah: (Minaean, then Mecca).
Almaqah Allah: (City of Saba, then Mecca).
Allah Taa'la, the most high Allah: (Ka'ba, Mecca).

Thus Allah has many forms. It certainly is not the 'Christian God' with an Arab name. The ilah, El-Lah or Al-Lah predates Christianity by 2.000 years. The only disputes range over whether Al-Lah is the moon or Sun god. Given the pastoral nature of poor Bedouin society, it is likely that Al-Lah would have been a moon deity. Agricultural areas like Egypt and parts of Syria, which had settled populations and urban centers worshipped a Sun god. For the Arabs it is likely that they reversed the genders. El-Lah was a male moon deity married to Allat or a Sun goddess, who bequeathed to El-Lah 3 daughters.

In any event, suggesting that this thing Allah is the same as the Christian or Jewish god is incorrect and historically ignorant.