HARO – Best journalist queries overall
Reporter Connection – Free journalist queries
ProfNet – Paid journalist queries
If you want to read Op-Ed’s from mainstream newspapers like the New York Times etc, you can find them all here:
You can also find sites like this on exactly how to submit an Op-Ed to different media.
PRLog.com – Free Press Releases
PRWeb.com – Not free, but better backlinks
List of contacts for major media by general industry: