Also, look into blogger networks if you have a blog connected with your site. These CAN prove valuable if the network is large enough to have bloggers in your site's industry niche. I've had some luck recruiting people that would post my guest blog posts in addition to A > B and A > B > C link swaps. One major drawback is people join and forget it. So while some niche listings are long, many of the accounts are dormant and they are hard to contact through the network.
One more thing: find do follow forums in forums that cater to your niche. Post the link as source links when posting up discussions that mention your content. Of course, it can't be posted in an obvious way
