How to adjust clock for daylight savings time and get local sun rise/set time?

For home automation projects using based on time how do you get local sun set/rise times to turn lights on/off and adjust for daylight savings time.

I have an Ethernet shield so I can get accurate time from an NTP times server on the Internet.

Any suggestion?

Any suggestion?

Don't bother?
An ambient light sensor should deliver what you want, and account for foul weather as well.