The websites that are the most useful for updates on space weather conditions are as follows:
NOAA Space Weather Center – This is a major, and official, source for space weather warnings and data about the current conditions using satellite and ground-based data
Spaceweather.com – This resource gives you a popularized synopsis of the current space weather conditions. It includes amateur photos of aurora, and stories related to the latest solar storm event.
International Space Environment Services – The international version of NOAA’s Space Environment Center.
NASA Spacewarn Bulletin – Updates on satellites, launches, orbit decays.
The Space Weather Journal – The American Geophysical Union has created a journal for space weather researchers to publish their findings.
Space Weather Services – The Australian space weather service, with a particular emphasis on radio interference issues caused by solar flares.