Links
Below are links to more on chess tactics; let me know of others and they will be added:
The wiki page on the subject is here.
Chess cafe tactics puzzles here.
Chess.com server: http://www.chess.com/tactics/
Tactics trainer: https://chess24.com/en/learn/tactics-trainer
Chess tempo: http://chesstempo.com/chess-tactics.html
http://www.ukchessblogger.com: an interesting chess blog. Check it out.
The Chessbase training site is here.
A new source for more tactical instruction: https://www.chessable.com/chess-tactics/
Dave Regis's site, the Exeter Chess Club Coaching Page, has an outstanding collection of free lessons on many aspects of the game, including chess tactics.
Dan Heisman's site, www.danheisman.com, contains a wealth of fine instructional material of various sorts, again including chess tactics, that may be of interest to you if you like this site.
www.professorchess.com is still another first-rate source of online instruction: chess tactics and more; some of it is free.
The Chess Cafe, of course, has lots of good stuff, including a fine links page.
Michael Goeller has an extensive index of good online chess resources, along with some other interesting material devised by the author.
Mark Weeks's "About Chess" page is another great place to go to find learning materials -- his own, and links to those of others.
The University of Pittsburgh Chess Club Page has another impressive collection of links.
The Reluctant Messenger's site also has links to good stuff on chess tactics.
The Chess Drum has a useful section in its chess academy section on chess tactics; it includes some very nice exercises that I recommend.
Rick Kennedy has an interesting new blog up on the Jerome Gambit.
Come back soon for more.