"Improving the Maintainability of Automated Test Suites" by Cem Kaner
http://www.kaner.com/lawst1.htm


"Test Automation Snake Oil" by James Bach
http://www.bonsai.com/swc/resources/testing-snakeoil.html


"Totally Data-Driven Automated Testing - A White Paper" by Keith Zambelich
http://www.sqa-test.com/w_paper1.html


"Essays on Automation" by Quality Tree Software
http://www.qualitytree.com/autotest/autotest.htm

These articles will help explain the economics of automation, identifying those places where it is feasible and unfeasible.