Linguist List -- a great resource with many different kinds of things; you can subscribe to an e-mail feed, or just use them online.
Ask a Linguist -- a service of Linguist List, where students can ask questions and get answers from linguists
mosling -- a mailing list for information for Moscow linguists
Tools for drawing trees:
the Arborwin font (for Windows or Mac)
The font itself (a True-Type font) is available for sale here. A Word document that shows the “code” for drawing pieces of trees.