Journals:
International Journal of Corpus Linguistics
Corpus Linguistics and Linguistic Theory
Tools and resources:
WordSmith tools
Xaira (for further documentation see)
Free online corpora:
CoCA (Corpus of Contemporary American English)
CoHA (Corpus of Historical American English)
TIME (TIME Magazine Corpus of American English)
BNC (BYU interface to the British National Corpus)
Webcorp (an interface that lets you analyse the web using corpus linguistic tools )