The Jet Lag Rooster
Type in where you're going, where you're coming from, and when you're going and The Jet Lag Rooster, by Jay Olson, who works in the psych department at Simon Fraser, will tell you when to seek out and avoid light in order to avoid jet lag.

Details:

Jet lag occurs when your body clock is out of sync with the environment. It can cause health problems and reduced alertness (Kolla & Auger, 2011).

Jet Lag Rooster works by shifting your body clock to the new time zone. It is free, simple, and effective.

Free. Jet Lag Rooster does not cost you any money.

Simple. Just enter your trip details and Jet Lag Rooster gives you a plan to reduce jet lag. You can email this plan to your smart phone, so the guidelines pop up as reminders during your trip.

Effective. Research shows that light exposure can shift your body clock (Eastman & Burgess, 2009; Kolla & Auger, 2011). Light exposure -- for example going outside in sunlight -- at the right times can reduce jet lag. Jet Lag Rooster creates an individual plan suggesting when to seek and avoid light, based on your own trip and body clock. People who follow these suggestions report less jet lag (Lieberman, 2003). In some cases, shifting your body clock before your trip could prevent jet lag completely (Burgess et al., 2003).

See an example jet lag plan, or get started by entering your trip details on the prevent jet lag page.

Here's the jet lag plan I made for a pretend trip to Paris on Sunday:

More here.