I would recommend to take a look at the website of Meditation and Mindfulness Research Group at Liverpool John Moores University. They not only present the results of various studies but also explain those in simpler, not-too-scientific terms. In their research blog they discuss neuroplasticity and meditation, neural mechanisms of attentional control in mindfulness meditation or Cognition and Emotion in Meditation, to name a few.
This article also seems to nicely sum up and group the effects of meditation with links to peer-reviewed articles.