Winning Writers, founded in 2001, is an excellent resource for poets who are interested in keeping up with poetry contests and other literary news. The site is included on the list of 101 Best Websites for Writers by Writer's Digest , and received the Truly Useful Site Award (well-deserved, I would add) in 2006 from Preditors & Editors.
The War Poetry Contest, which focuses on the theme of war, is their current contest. May 31st is the deadline. I'm sorry for the short notice, but if you are inspired to, and can complete up to three poems on war before the deadline, please check out their submission guidelines and go for it! You can enter online, which is convenient, since the end-of-month deadline would mean mailed entries would not be received on time.
Of course, if you miss the deadline for the War Poetry Contest, there are many other upcoming contests you can enter.
I would be happy to hear about any successes, so please send me your comments.