TechSoup for Libraries (love these guys, if you are not a regular follower or user of their resources, I would strongly encourage you to be) covers some best practises for mobile computer labs in their latest Edge Initiatives benchmarks. In this post, they look at a number of success stories:
* Poudre River Public Library District (Fort Collins, CO), where their suitcase lab brings training into people's living rooms,
* Lamar Public Library (Lamar, CO) serving a rural population of approx 8,000 people in se
* Free Library of Philadelphia (PA), with their shiny Techmobile and community Hotspots.