(__ABC__)

• Desperate Housewives; May 15
• Castle; May 16
• Grey's Anatomy; May 19
• The Middle; May 25
• Modern Family; May 25

Source [http://www.tvline.com/2011/03/abc-announces-16-may-season-finales/]

(__CBS__)

• How I Met Your Mother; May 16
• Criminal Minds; May 18
• Big Bang Theory; May 19
• The Mentalist; May 19 (2 hours)

Source [http://www.tvguide.com/News/CBS-Finale-Dates-1031176.aspx]

(__CW__)

• Smallville; May 13 (2 hour series finale)
• Vampire Diaries; May 12
• Supernatural; May 20 (2 hours)

Source [http://www.tvline.com/2011/02/the-cw-season-finale-dates-2011/#more-203430]

(__FOX__)

• Fringe; May 6
• Bones; May 19
• Raising Hope; May 17
• House; May 23
• Glee; May 24

(__FX__)

• Justified; May 4

(__NBC__)

• Community; May 12 (hour long; special awesome guest star!)
• The Office; May 19 (hour long)
• Parks and Recreation; May 19 (hour long; starts @ 10pm)
• SNL; May 21

Source [http://www.tvline.com/2011/03/nbc-announces-spring-finale-dates/]