Ask HN: How can I determine what my salary should be?

I am working in the Bay Area as a network engineer and will be looking for a new position soon. However, I have relatively few contacts in the same field as I am and it is difficult for me to gauge what my salary should be. Are there any accurate tools for this?

I am a network engineer, cisco CCNP certified, about 10 years of experience and also have somewhat senior unix, linux and windows skills...