Bulk email

I’ve had a few websites for awhile now. I’ve done the yahoo sponsor search, google adwords, and everything else out there. After learning about email marketing I believe I could have my best sucess with this. I’m not trying to sell anything I’m just trying to get people to join my social network website (writers). So what I need to know is how do I get started? Where do I find email lists? What’s that best free program I can use to send bulk emails? I’m not trying to invest any money in this so I need to know free ways to do this (I know about the pay ways). So if anybody knows anything please let me know because I need my website to grow faster.