After Effects CC (12.1) adds an option in the Precompose dialog box for this, to trim the precomposition duration to the duration of selected layers.

See this page for details:
http://adobe.ly/AE_CC_12dot1_details

Here you go.

Scripting changes in After Effects CS6: http://adobe.ly/NP67Uu

scripting changes in After Effects CS6, plus new scripting guide (yes, really): http://adobe.ly/NP67Uu

Here's an early post with the essentials about what has changed: "Scripting changes in After Effects CS5"

I just talked with a couple of the After Effects software engineers about the Popup control. For now, this control is just used internally by layer styles. It doesn't work for custom effects / animation presets. If you want this functionality, please enter a feature request using the feature-request...

Here's a link to a blog post that gives information about the new and changed features in a sparse outline format: After Effects CS4 scripting changes

I'm working on updating the After Effects scripting guide for CS4. In addition to documenting the new features, I'm fixing long-standing errors, adding examples, and otherwise trying to make the document better. So, what do you want to see added, fixed, or changed? I've posted a copy of the After Ef...

Please take a moment to take the Adobe Creative Suite scripting survey: http://niemannross.com/limesurvey/index.php?sid=83733&lang=en This survey will help Adobe understand the needs of people using ExtendScript, AppleScript, VBScript and other scripting languages with Adobe Creative Suite. Ther...

Jeff Almasol has posted an early version of a script that converts paths on shape layers to masks.

Click for new scripts for After Effects CS3, including a keyboard shortcuts Enjoy. Thank Jeff Almasol. This download contains scripts for editing keyboard shortcuts (KeyEd Up), launching scripts (Launch Pad), creating project folder hierarchies (Folder Setup), converting Adobe Swatch Exchange (.ase...

It appears that Impudent1 has reorganized his website a bit, and this script has moved. I found it here:

http://www.leapfrog-productions.com/Scripts

I also just added a link to this script from After Effects CS3 Help:

"Organize and view items in the Project panel"

It appears that Impudent1 has reorganized his website a bit, and this script has moved. I found it here:

http://www.leapfrog-productions.com/Scripts

I also just added a link to this script from After Effects CS3 Help:

"Select a color or edit a gradient"

This is a very handy animation preset. I just added a link to this thread from the "Keying overview" section of After Effects CS3 Help. One thing that I mention there is that the version of the Keylight effect that this animation preset refers to is different from the one included with Aft...