I wanted to look up the duration of my flight, but sadly I could only find arrival and departure time. This would mean that I would still have to look up time zones. Is there a website that can do this?
If you have a specific flight in mind, with the flight number, you can use FlightAware, which has pretty good global coverage for most airlines. The duration is shown on the right: actual duration for completed flights and scheduled duration for upcoming/in progress ones.
Hipmunk gives you a nice graphical representation of flights and their duration.