Me on a time lapse from James Broad on Vimeo.

This video is what you can create (that or something similar) by following these steps on your Mac.

Step 1

Download & install a command line webcam capture utility, we will be using isightcapture
Open the DMG and extract the binary to /usr/bin/
sudo cp /Volumes/isightcapture1_1/isightcapture /usr/bin/

Step 2

Set up new directory to work in.
Lets use ~/captures/
cd ~
mkdir captures
mkdir captures/scripts
mkdir captures/series

Step 3

Make script to take photo and save it
cd ~/captures/scripts

Insert the contents into the file:

CAPTURE="isightcapture -t jpg"
cd $HOME/captures
D1=`date +%y%m%d/%H`
D2=`date +%y%m%d.%H%M%S`

# If the date directory does not exist, create it
if [ ! -d $D1 ] ; then
mkdir -p $D1

# Construct the filename and path and capture a pic

# Make a symlinked image of the last photo taken
if [ -h 'last.jpg' ] ; then
rm last.jpg
ln -s $FN last.jpg

Save and quit (:wq)

To be able to run this script we need to allow execution permission on this file.

chmod a+x

Step 4

Put your capture script on cron
crontab -e

Write the contents:

* * * * * ~/captures/scripts/

Step 5

Install a utility to convert a series of images to a movie. We will be using ffmpeg
cd /tmp/
svn checkout svn:// ffmpeg
cd ffmpeg

We need to install ffmpeg to our machine, this process is going to basically compile the code. Hopefully nothing will go wrong for you here, if it does though, take a look on

./configure --enable-shared --disable-mmx
sudo make
sudo make install

Step 5

Make script to grab photos and run them through ffmpeg
mkdir ~/captures/videos/
cd ~/captures/scripts

Write the contents to the file:

rm ~/captures/series/*.jpg
for i in `find ~/captures -name '*.jpg'` ;
#Write the filename to be friendly with ffmpeg's odd filename input
FILENAME=`printf '%03d.jpg' $COUNTER`
cp $i ~/captures/series/$FILENAME
nice ffmpeg -r 20 -vcodec copy  -i ~/captures/series/%3d.jpg ~/captures/videos/

Again setting the permissions to be able to run the script and then run it to generate a movie based on the images taken so far.

chmod a+x

Step 6

View the finished result
Browse in finder to your home directory > captures/videos and watch the result.