These are the projects that I am currently aware of that propose to ship code thru the network to be executed in switches in order to deploy new network function quickly. Here is a good introduction to the ideas.
The Messenger Project: Inquiry into foundations for distributed computing
SwitchWare: Accelerating Network Evolution
Active Networks: User code in Switches in support of better protocols. (Good survey)
WebOS: Protocols for better computing thru distribution
ABone: Active Network Backbone
Planet Lab
Donut Lab

My ideas in this area

Digital Silk Road Synergy: Ultra Low Cost Money Transactions
Glass: Network with Integrity but not Secrecy
My Unripe Proposal