I'm a big fan of tracking all of my brewing activity in a log book. And rather than just print out the recipe and stick it in the log, I try to track what actually happened, instead of what the recipe says should have happened. Frequently the two are quite different.
There are a few free brew log templates on the net. I've tried Randy Mosher's from Radical Brewing. I've tried files put together by helpful brewers on various forums. But I've always had a couple problems. First, they don't really track information the way I want to track it. And second, they just don't look very good.
Although it's a PDF on this site, I created it using almost nothing but HTML and CSS. The two temperature tracking charts are the only exceptions, they are images generated Google's Chart Tools. And because they are generated, I can't quite get them to look exactly the way I want.
It's not perfect, but it's a good starting point. If you want to use it, and you don't mind having the wrong brewery name at the top, feel free.
Updated 10/20/10: New version increases the line height, adds a section for notes and gravity checks and tweaks the layout of the Boil/Whirlpool sections.
Updated 11/16/10: Better grids on the fermentation- and mash-tracking charts. Moved the Gravity/Efficiency section below the mash-tracking chart.
Updated 1/17/11: Expanded to two pages. I removed the whirlpool section because I never used it. Whirlpooling is a process that doesn't really change batch to batch, so there's no reason to track it in the log. Added sections for Aeration/Oxygenation, Forced Fermentation testing, Fermentation notes and Packaging. Where the log tracks expected and actual values, I've added a | in the field to demarcate the two values.
Updated 2/14/11: New logo, which won't matter to anyone but me. Added a section for Apparent Degree of Fermentation (ADF). Added a water-loss worksheet that's probably too elaborate and weird. The goal is to have a place where I can see how much water I'll need and how much beer I'll end up with.