Here are two software CDs designed to assist beginners
1000 x Checkmates. The first part of the CD consists of a small database explaining all possible mate motifs in 15 themes. The main database contains 1000 mating tasks all gathered from actual games. Each move of the mating side is connected to a training question. Scoring.
Chess Tactics Art 3.0. Contains about 1,250 exercises classified according to three criteria: 1) Tactical methods (Annihilation of Defense, Distraction, Decoy, Open attack, Opening of a file, Space clearance, X-ray attack, Interception, etc); 2) Combination motifs (Geometrical motif, Weakness of a file, Opposing, A piece is overloaded, Bad position of the pieces, Limited material, etc); 3) Difficulty (ELO 1600-2300).
Intensive Chess Tactics. This chess tactics training software CD contains well over 4000 tactical positions with training questions, categorized in more than 120 databases according to the author's newly developed theme classification. Windows 95/98/ME/2000/XP
The Magic of Chess Tactics. Claus Dieter Meyer and Karsten Muller provide training exercises and a teaching approach for more complex tactics.
Of course, combinations don't just happen. I recommend the following two books for many reasons, especially because they provide consideration of the entire game, not just the tactics.
The King-Hunt, John Nunn, William Cozens. An old classic of king hunts, driving the king towards the center of the board and finding miraculous mates. The book, improved by Nunn, has well-annotated, timeless classics, and now some modern material.
Published in 1978, Leonid Shamkovich's The Modern Chess Sacrifice was one of the first books to classify sacrifices and combinations. Whether you own the book or not, I recommend that you enjoy this collection of the games used in the book. Chapters include Sacrifice of pursuit, the Developing sacrifice, the Preventative sacrifice, the retarding sacrifice, and the strategic sacrifice. A fun read, with interesting annotations and an excellent selection of games.
Storming the Barricades, Larry Christiansen. More king hunts, but more: General considerations on attacking, ripping apart the kingside, and Christiansen's 11 favorite attacking games of the 1990s, all well annotated in readable verse.
Here are a couple of books for those who prefer a somewhat more structured, advanced approach with fuller explanations.
Lethal Weapons. GM Julian Hodgson reveals his ten secret rules of play of attacking play and explores the tactics of several GM games in these two videos.
Krushing Attacks. Young chess talent Irina Krush analyzes some of her best games and combinations from her rapidly ascending chess career. A chess master at the age of twelve, this young woman is blazing a trail for young American chessplayers everywhere.
Attack with Confidence. GM Danny King helps you to build up an attack from a sound basis and spotlight the vital weaknesses around your opponent's king.
20:20 Calculation. Danny King is back to let you into the secrets of 20:20 calculation, helping you to cut through the fog and home in on what's crucial.