How much pre-programming do you guys do?

I'm a VB.Net programmer, and I usually don't do pre-programming but seeing as I'm stranded with an iPod but no laptop, I've been doing some extensive pre-programming for my upcoming keyword tool. How many of you guys (doesn't matter what language) pre-program, and to what extent?

For those unfamiliar with VB, windows in an application are called forms. So far, I've diagrammed every form I plan on implementing, and named/defined the function of every element within those forms; I'm about to start creating a detailed algorithm map, even down to the individual functions. Basically, everything but writing the actual code itself so that when I do get access to a computer, I'll be able to knock out the code in a matter of an hour or two instead of a day or two (that said, with all the time I'm spending pre-programming, it'll probably even out).

I don't do any pre programming. I have a good hunch of what I want, and I just start programming and improvising and revising. It works very well for me.

If I'm working with other people we usually have lots of dfds, schema maps and uml floating around, most of the stuff I do by myself is schemaless and classless so I just write whatever's in my head and keep a war diary and changelog of what I did, when and why in a notebook.

Yeah, in the past I've always freestyled my code but now that I'm sitting around with no computer I am resorting to preprogramming to stay productive. Say, does anyone know if there's a keyword tool or service that tells you what all your existing site's potential keywords are? It's one of the main features in this tool but I don't want to waste my time on something that already exists. The end result will be able to give results similar to freeseoreport, but I would like it to be application based.

I don't really do any pre-programming, but I write the tests first.

Not a whole lot. I just start writing the code and then improve it where need be.

Having a clear view of what you're going to implement is vital to any largeish project and considered good practice even for smaller projects where you'd think of it as overkill.
You might waste 10 minutes now and then on small projects, but it will help you in the long run.

Sadly, I also like to write code on the fly.

I usually have the basic skeleton ready for common projects such as scrapers, account creators etc, but normally I code from scratch.