Last month a new IBM Redbook titled DB2 Virtualization has been published. In the book the authors first explain what can be virtualized (servers, storage, network), then talk about about technologies related to virtualization. What I found very interesting was a longer section about sub-capacity licensing, i.e., how DB2 is licensed for some of the virtual environment (how you can save money or not), as well as an overview about the different virtualization products and solutions (incl. Power HyperVisor, VMWare, Linux Kernel-based Virtual Machine). That chapter also includes information about many great DB2 features, such as everything "autonomic", "self-", and "auto-".
The remaining chapters of the DB2 Virtualization book provide in-depth coverage of DB2 in several virtualization environments. Even if you are not planning on running DB2 in a virtual machine, I still recommend reading that book because it gives a good introduction into that topic combined with an overview of current technologies and products.
[More links on virtual appliances are in an older post.]