NEMO ambassador Adam C. has put together an awesome little primer for folks that want to get into timelapse photography. Here's the cliffnotes version (full version here):
STEP 1: Buy an intervalometer off Amazon.com.
STEP 2: Take your intervalometer and have at it.
STEP 3: Find what you want to timelapse and have fun.
STEP 4: Math.
STEP 5: Create the Timelapse (this part is super easy).
As a sampler, he put together this video to give some ideas and show some of the cool things that you can shoot. My favorite parts are the airport night scenes around 1:30.