Two recent books on metaphors worth looking at is Raymond Gibbs and Herbert Colston’s Interpreting Figurative Meaning and Benjamin K. Bergen’s Louder Than Words. Gibbs and Colston approaches metaphorical meaning from psycholinguistics and neuroscience while Bergen looks at meaning from the cutting-edge perspective of neuroimaging.
Both are worth a look. The Gibbs/Colston is harder to get through than the Bergen. The latter is definitely an easier read, written for those with little background on the subject.