Copyright infringement occurs when a third party uses one or your poems in an unauthorized manner. This could include republishing your poem without your permission, making derivative works of the poem or performing the poem in public. If you have registered your poem with the U.S. Copyright Office, you will be able to sue the infringer for attorney fees and statutory damages. For this reason, formal registration is very important.
Although it may seem onerous, you should copyright every poem you write so that all of your work will receive the protections afforded by copyright registration. It is not necessary to copyright your poems the instant you write them, but you should apply for a copyright before publishing your poems or making them available to the general public.
An alternative to registering your poems one by one and paying multiple filing fees, which can become costly very quickly, is to publish a series of poems in a single volume. When you copyright an anthology or book of your poetry, you only have to file one application and pay the filing fee once.
To register your poetry with the U.S. Copyright Office, you can either file a paper application or file online through the Copyright Office website. The filing fee for an online application is $35 as of 2012, while the paper fee is $50. You can file online at http://www.copyright.gov/forms/. You'll need to provide some basic information, copies of your poetry and the filing fee.