>>> HF Propagation Primer <<< - Flash presentation covering the basics - must see!

ARRL Propagation Forecast Bulletins
AC6V's HAM and DX REFERENCE GUIDE
DF5AI Amateur radio propagation studies - Excellent page, features "Beamfinder software".
DX-LIST - for Hams wishing to receive DX information via email. DX-LIST Archives
DX-Listener's Club and their excellent Solar Terrestrial Activity Report
The DX Notebook
DX SUMMIT - DX Clusters and more
HF BEACONS
hfradio.org - This links to their dynamic propagation page
IOTA - Islands On The Air
IPS Radio and Space Services- The Austrailian Space Weather Agency
K4UTE Prefix Finder
NG3K Amateur Radio Contest/DX Page
The OPDX Bulletin
Realtime Sudden Ionospheric Disturbance Monitor - Straight from the Moore Observatory, University of Louisville, USA
Solar Terrestrial Dispatch
WorldWide QSL Bureaus
W1AW DX Bulletins
W1AW General Bulletin
WWV Recent Solar Indices - Probably the best single source of recent solar/geomagnetic indices.

DX Clusters
from OH2AQ's DX SUMMIT

137kHz, 1.8MHz, 3.5MHz, 7MHz, 10MHz, 14MHz, 18MHz, 21MHz, 24MHz, 28MHz, 50MHz, 70MHz, 144MHz, 430MHz, 1.2GHz, 10GHz, Beacon, Digital, IOTA, QRP, Satellite

DXCC COUNTRY LIST
ONLINE MAP CREATION
SHORTWAVE BROADCASTS OF INTEREST TO DX'RS

    Realtime K-Index courtesy Borre Holmeslet, The Auroral Observatory University of Tromsø, Norway