Have a look at Jetty. It can be invoked from a standard Main invocation, and handles servlet containers pretty well (GWT debugging is hosted in a Jetty environment, for example).
I’ve used this for debugging Lift applications, and been pretty impressed.
To forward requests through IIS to Jetty you can try mod_jk. The problem is that IIS and Java/JSP don’t Just Work because IIS needs add-ons to support the loading of the VM and the reflection of JSP/Java content. There is an excellent article on how this can be done here.