One important trend in regard to SOA deployment options is virtualization. Virtualization is an important enabler of verstility and mobilty of services. A relatively new trend in the realm of virtualization is Software appliances, which can even serve as an on-site alternative to the Software as a Service concept. Software appliances also provide a viable option for packaging services for deployment.
The idea behind a software appliance is to isolate the software from the OS, wrapping it with the set of capabilities (parts of the OS) that are needed for its operation. The idea is to deploy a working instance of software appliance regardless of the host OS - i.e. you get a single image you can run on a clean machine, a VMWare, an OS installation etc. Software appliances have reduced memory and resource foot-print vs. deploying a full blown virtual server the a software package installed on it. Another advantage is that you do not need to worry about certifying the application to the OS, driver incompatibilities etc.
