Suggestions for marketing free ezine?

I own an online ezine "The Virtual Evolution" which focuses on articles by entrepreneurs for entrepreneurs. We are always seeking 'fresh voices' to write articles for us and I am trying to figure out how to attract subscribers. The ezine is free; all costs are covered through advertising.

I have been contacting entrepreneur programs at US colleges to see if they are interested in utilizing this free resource but I could use some additional suggestion on how to get more subscribers (and writers).