Two good textbooks/surveys are:
1. Torsten Persson and Guido Tabellini. 2000. Political Economics:
Explaining Economic Policy. The MIT Press.
2. Timothy Besley. 2006. Principled Agents?
The Political Economy of Good Government. Oxford University Press.
For modern Marxian political economy, check out John Romer of Yale: http://pantheon.yale.edu/~jer39/