The following is a list of learning resources I have come across and found helpful.

Database Design

The following books can be helpful.

Hernandez, M. J. (2003). Database design for mere mortals: a hands-on guide to relational database design (2nd ed.) Boston: Addison-Wesley.

Riordan, R. M. (2005). Designing effective database systems. Boston: Addison-Wesley.

PostgreSQL

The documentation included with PostgreSQL is quite extensive and helpful. The PostgreSQL mailing lists are also very active and helpful. The following book contains some additional useful information.

Douglas, K., & Douglas, S. (2006). PostgreSQL (2nd ed.). Indianapolis, IN:  Sams Publishing.

SQL

There are many books about SQL and the more recent ones contain information about the latest standards.

Celko, J. (2005). Joe Celko's SQL programming style. San Francisco: Morgan Kaufmann/Elsevier.

Kriegel, A., & Trukhnov, B. M. (2003). SQL bible. New York: John Wiley & Sons.

Taylor, A. G. (2003). SQL for dummies (5th ed.).  Indianapolis, IN: Wiley Publishing.

Wilton, P., & Colby, J. W. (2005). Beginning SQL. Indianapolis, IN: Wiley Publishing.

GUI Design

Studies regarding GUI usability have been done and considerable information is available. The following provide some useful guidelines for developing user GUIs.

Gunderloy, M. (2005). Developer to designer: GUI design for the busy developer. San Francisco: Sybex.

Java

Java information and source code examples abound on the Internet. The Sun Microsystems tutorials are a good place to start. There is also no shortage of good Java books. Here is an up-to-date volume.

Richardson, W. C., Avondolio, D., Vitale, J., Schrager, S., Mitchell, M. W., & Scanlon, J. (2005). Professional Java, JDK 5 edition . Indianapolis, IN: Wiley Publishing.

Eclipse and the RCP

I found the Eclipse help system, documentation, and mail lists on the Eclipse website to be only moderately helpful. Finding specific information and good code examples can be difficult. I would rate the following book as essential reading. It is based on the current (3.1) version of Eclipse, provides clear explanations at a good level of detail, and is generally well done.

McAffer, J., & Lemieux, J.-M. (2005). Eclipse Rich Client Platform: designing, coding, and packaging Java applications. Boston: Addison-Wesley.

The following books are well done and fairly useful, although they cover Eclipse version 3.0 and there have been some significant changes with version 3.1. Unfortunately, this reduces their relevance, perhaps less of an issue for the Scarpino et al. book.

Daum, B. (2004). Professional Eclipse 3 for Java developers. Chichester, England: John Wiley & Sons.

D'Anjou, J., Fairbrother, S., Kehn, D., Kellerman, J., & McCarthy, P. (2005). The Java developer's guide to Eclipse (2nd ed.). Boston: Addison-Wesley.

Scarpino, M., Holder, S., Ng, S., & Mihalkovic, L. (2004). SWT/JFace in action: GUI design with Eclipse 3.0. Greenwich, CT: Manning Publications.

The following book is very new and I haven't had a chance to look at it, but it appears useful.

Arthorne, J., & Laffra, C. (2005). Official Eclipse 3.0 FAQs. Boston: Addison-Wesley.

HTML, XHTML,Cascading Style Sheets, and XML

Free tutorials for all these subjects are available from W3 Schools. Many books have been written about these subjects and a few are listed below.

Kennedy, B., & Musciano, C. (2002). HTML & XHTML: the definitive guide (5th ed.). Sebastopol, CA: O'Reilly Media.

Meyer, M. (2004). Cascading Style Sheets: the definitive guide (2nd ed.). Sebastopol, CA: O'Reilly Media.

Ray, E. T. (2003). Learning XML (2nd ed.). Sebastopol, CA: O'Reilly Media.