In reply to Melvin Alexander.

Yes, there is a huge amount of research on statistical classification schemes, and classifying spam is often a canonical example. The UC Irvine Machine Learning Repository has many spam data sets, if you'd like to try your hand at this classification problem. The spam data collected by George Forman (HP Labs) is analyzed heavily in the classic text _The Elements of Statistical Learning_ by Hastie, Tibshirani, and Friedman.