Hello,
the presentation I did during Fosdem in Brussels last weekend is available at: http://www.kamailio.org/events/2011-fosdem/dcm-sip-web-lua.pdf
The focus was to show how to interact with Kamailio via HTTP and how Kamailio can interact with Web services via HTTP, using Lua to make it easier. There are slides for a demo config of sending asynchronous notifications to Twitter on missed calls (using modules app_lua, mqueue, sqlops and rtimer).
Cheers, Daniel