Computer programming is the closest thing you're going to get to D&D's arcane wizardry in the real world. This analogy, which I am sure other gamers have explored in the past, though I could find no articles online about it, provides some cool insights and ideas.
Programs are spells. Just like a spell, a program performs a specific task, and a program's possible applications vary widely. Programming languages correspond to different styles of magic and spell notations. Just like a wizard, a computer programmer must study these intricacies in excruciating detail for many years in order to master the art.
A computer is akin to a spellbook (though much more powerful) in that it contains a collection of programs. The size of the program corresponds to spell level-large, complex programs take up more space and provide more functionality. A suite of applications or tools is like a collection of related lower level spells.
A program designed as a library does not have a clear corollary in D&D, but probably should. That is, the rules for a spell "template" or "building block" for use in creating more complex, intricate spells would be interesting to model. The closest thing 3E has is spell seeds for epic spells, but those are a short, concise list, as opposed to a player-extensible tool base.
In computers, there is a distinction between "users"-those who cast spells designed by others-and "programmers"-those who research new spells. This is the key insight and main conclusion of my thought train here: it would be fascinating to have a world where the "wizards" are the ones researching new spells, and are held in higher esteem than the unwashed masses who carry around spellbooks full of other people's work and blast off fireballs at people. (This is where Greg tells me that some obscure game system already exists where wielders of magic are known as "users" and "programmers," since this analogy is fairly obvious.) Perhaps I'll run a campaign in 4E once it comes out with such a distinction: wizards as programmers, sorcerers as users. Of course, such a setting would require careful consideration of spell research rules, something which Wizards themselves have admitted to being extremely challenging to implement and balance (well,
they said: "There will not be magic item creation rules for DM’s as we realize that as professional game designers we don’t even get it right every time," which is a similar issue to spell research, though admittedly even more difficult).
As a tangent, I really like the changes Wizards is implementing in 4E with respect to the D&D cosmology. You can read about them
here (scroll down to the bullet point beginning with "The D&D cosmology is being revised..."). The Feywild, the Shadowfell, the Elemental Chaos, the Astral Sea, the Nine Hells, the Abyss-it's all awesome stuff, and much more fun to design worlds around than the old elemental planes (which I agree were largely useless, or at least pretty boring). Hopefully it will be straightforward to drop my wizard/sorcerer idea into the updated setting.