Your best source for help in writing your philosophy paper is your professor or GSI. Tanner Philosophy Library also has some books that are excellent sources of information. If you need some help at 3:00 a.m. however, these sites might be helpful.
Jim Pryor's Guide to Writing a Philosophy Paper (NYU)
A Sample Philosophy Paper by Angela Mendelovici (Professor at University of Western Ontario). Paper is annotated which provides helpful comments about how and what you say; but note, citation formats can matter, check with your instructor.
Logic in Argumentative Writing from the Purdue OWL
Logical Fallacies Handlist: Arguments to Avoid When Writing (from Professor L. Kp Wheeler, Carson-Newman University)
Peter Horban's Guide to Writing a Philosophy Paper (Simon Fraser University)
The Chicago Manual of Style Online (16th edition, 2010).
APA Documentation Guide, (6th edition, 2009 of the Publication Manual of the American Psychological Association.)
MLA Formatting and Style Guide (This resource, updated to reflect the MLA Handbook for Writers of Research Papers (7th ed.) and the MLA Style Manual and Guide to Scholarly Publishing (3rd ed.)