From Penelope Trunk’s blog, Networking tips for introverts. An excerpt:

Help others. For instance, send leads to jobseekers you know. You don’t have to talk to them, but they’ll remember the favor and view you as a friend. My husband maintains a list of specialized job sites that he sends to friends who have recently lost jobs. They’re grateful for his help and the time it saves them, while my husband is grateful that he only has to research job sites instead of having to talk to people.