Programming Spiders, Bots, and Aggregators in Java
One of the articles in the JavaPro magazine I bought was a review for Programming Spiders, Bots, and Aggregators in Java which looks pretty interesting. The Journal has a aggregator piece which I'm working on also (jdom + jdring + hsqldb codenamed "Jagger"), so this might be a good book to pick up.
-Russ