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?

Doug101:
Any suggestion?

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