IP-based sensor networks are a rapidly emerging hot topic in both academia and the industry. The open source uIP stack from the Contiki operating system, first released in 2001, is used in IP-enabled products and systems from hundreds of companies, ranging from pico-satellites, airplanes, and car engines, to worldwide freighter container tracking systems, ship control systems, and oil boring and pipeline monitoring systems. In October 2008 Cisco Systems released uIPv6, the world's smallest fully compliant IPv6 stack, for Contiki. During this tutorial, participants will get started with building IP-based sensor networks with Contiki and uIP, and get hands-on experience with developing, compiling, and running IP-based software on sensornet hardware, setting up IP networking to the sensor network, and getting performance metrics (power, throughput, latency) from a running network. We use a combination of Tmote Sky and Sentilla JCreate motes as the hardware platform. We provide Tmote Skys and JCreates for participants to borrow during the tutorial. To avoid installation of compilers and tools, participants will use the Instant Contiki development environment, a complete development environment in a single-file download consisting of a VMWare virtual machine with all Contiki software development tools installed: http://www.sics.se/contiki/instant-contiki.html