Greyline Map Real time!
hfradio.org For those who can't get enough propagation info
Ionosphere Prediction Service From Australia
The National Solar Observatory/Sacramento Peak Good solar pictures
NCDXF/IARU International Beacon Network Complete listing with times, freqs, etc.
Propagation Primer by AE4RV
RealTime MUF Map Condx at a glance - greyline, aurora zone, MUF, etc.
SEC Data Library Virtually complete solar-geomagnetic records plus much more
SOHO Synoptic Data Solar images from many sources
Solar Activity Report from Big Bear Solar Observatory
Solar Terrestrial Dispatch All about the Sun - technical but interesting
Space Weather Yet another good source of solar and ionospheric data
Sunspot Cycle 23 Definitive Cycle 23 info
Sunspot Cycle Predictions
Sunspot Index Data Center
Today's Space Weather including latest K index From Boulder, updated every 3h
TEN METER INFO
G3USF's Beacon List Very thorough list also includes other HF band beacons
28 MHz Beacons British site with many links to beacon info.
WJ5O Everything you wanted to know about 10M....