try this:
http://www.wam.umd.edu/~rfradkin/alphapage.html
Actually, the current order developed in several stages. True that the "foundation" for our order, from the Latin alphabet went back to the Greek (which the Romans borrowed via the Etruscans), but the Greeks themselves borrowed most of their letters AND their traditional order from Phoenician traders, early in the first millennium BC.
Indeed the Greeks even, in most cases, used the Phoenician NAMES when they started out (though not for letters added later). Thus, for example, "alpha" and "beta" mean absolutely nothing in Greek! But the Phoenician names "aleph" and "beth" mean "ox" and "house", respectively. Those Phoenician words BEGAN with the sound of the letter (originally a stylized picture of the item). [Note that the WORD "alphabet" gives away the Semitic origins.]
The Phoenicians themselves did NOT invent the alphabet nor the names and order. Rather, it was their heritage from the earliest development of the alphabetic system ca. 2000 B.C. by speakers of a Semitic language (relative to later Hebrew, Aramaic and Phoenician) in the region of the Sinai peninsula.
We find evidence of this order preceding the Phoenician to Greek borrowing in old "acrostic" poems such as those found in the Hebrew Bible (in which each verse or stanza begins with successive letters of the Hebrew alphabet). The most famous example is Psalm 119, which is still printed with stanza headings including the letter names (and often symbol) in many English Bibles.
But even further back -- in the MID-2nd millennium BC we have found 'school texts' from the ancient Syrian port city of Ugarit in which their version of the alphabet was written out in the same order (though with a few additions - letters that dropped out of later alphabets). There is ONE letter pair that seems to sometimes have varied (we don't know why), though otherwise the order has been amazingly stable.
But where did this ANCIENT order come from?
Sorry, but we simply do not know! It makes sense to suggest that the PRACTICE of having an established order was simply to make it easier to teach and learn (just as it serves us today). But we'd have to know a bit more about the earliest history of these letters to know the exact reason for this exact order. A couple of guesses (no more than that):
a) the first alphabet was likely adapted (the idea at least) from one small part of the complex system of Egyptian hieroglyphs (a sub-set of symbols used to transcribe the sound of unfamiliar, foreign names, where the reader NEEDED some indication of the sound to be able to know what to say) -- could be that the Egyptian system had or suggested something of this order...
and/or
b) a more involved "mnemonic device" early users of the alphabet may have coined some set of devices that strung several of these WORD letter-names together... some sort of memory device, maybe even a simple set of sentences or a storyline (do the groupings "mem, nun" ["water, fish"], and "ayin, pe" ["eye, mouth"] hint at simple logical pairings or even a mnemonic sentence or storyline?
There is evidence in a few cases for clustering of related SOUNDS, and/or of the names of adjacent letters accounting for their grouping. (Seen in the Hebrew form -- "mem" and "nun" are adjacent, as are "chet" and "tet") It's also interesting that the LAST letter "tau", means simply "mark" or "sign", a very general word for a non-specific written symbol. (Interestingly, in the most ancient forms of the Semitic alphabet this letter looks like our "X", which is used in a similar way ... e.g., an illiterate person who cannot sign their name is asked to 'write their X')
(There is one other twist -- a SECOND 'standard order' that was continued in another version of alphabets that developed, including "South Semitic" dialects... the order still reflected in the Arabic alphabet.)
___________
This explains the order of the "core" of the alphabet, and is still seen rather clearly in the letters "A" to "T". Then, when Greeks or Romans invented a NEW letter -- brand new or a variation on an older older one -- to indicate some sound in their own language that they had NOT found a usable Phoenician letter for, they would either tack it on at the END of the list, or next to a related letter... which gives you a hint of how old various letters are.
Related letters together - I/J, U/V/W
Others added later - X, Y (a 're-borrowing' of the "Greek u" ['upsilon']), Z
This all explains, by the way, how "Z" came to be "zed" in British English. It was a LATER borrowing of the Greek "zeta" and was borrowed WITH the Greek name. The Romans had changed the letter names to simply make the SOUND of the letter + (usually) a vowel sound to make the whole thing pronounceable. (Some of the letters the Greeks had ADDED to the original Phoenician ones were named that way too.) When "zeta" was added to the Roman alphabet LATE, there were those who adap