Tools
We suggest you read and live by the DX Code of Conduct found here among other places.

Call sign look up QRZ.com

1 x 1 call sign look up

QSL Manager look up IK3QAR's site

QSL Manager look up QSLinfo.de

Impressive list of look up sites by K3WWP

Propagation tool: Grayline map

NG3K's list of upcoming announced DXpeditions and contest expeditions.
E
F T T San Diego DX Club
T T International DX Foundation
T T E B C G I K N S