"What it does: Provides custom microchips for everything from MP3 players to complex communications systems. Clients include Apple, Microsoft, and Kodak. Why it's growing: ESilicon is a truly virtual company, with no manufacturing capability of its own. Instead, it acts like a general contractor that oversees a large cadre of highly skilled subcontractors. Says CEO Jack Harding: "When times are bad, companies outsource to us, and when times are good, they hire us to get to market faster." "