Poetry can be published in literary magazines, some dedicated solely to poetry (such as Poet's Corner). Strong Verse is an example of online poetry magazines, which are growing in popularity. Books and poetry anthologies, while not as common, publish work by emerging and established poets alike.
2009 Poet's Market provides a valuable resource for poets: It lists various books, magazines, poetry contests and web publications, and gives contact information and submission guidelines.
Follow submission guidelines for each publication. Poems not meeting the basic criteria for submission are thrown out. Remember that editors receive plenty of work, and ignoring the guidelines results is a common filter--works not following the publication rules meet with rejection.
Considerations for publication guidelines include dates (some publication only accept submission during certain months), style and form, content (often books and magazines require a topic or theme) and word/page count. Adhering to submission guidelines increases your chance of actually having your poem read.
Make sure each poem is submitted properly. Guidelines give information on how and when poems can be submitted. Do not send an e-mail when traditional mail is the only acceptable form of submission. E-mail submissions require certain document types (.rtf, . doc, and .pdf). Use the proper formats (double spaced, font types).
Not all publications pay for published poems. Those that do pay for accepted work either pay per word, line or page. Once a poem is accepted, contract and payment information is sent to you, stating the publishing details. Read carefully to see if the terms are fair and acceptable.
Magazines and contests can charge reading/entry fees for poems. They should not be too high (generally under fifteen dollars). Be wary of publications, especially books, that require you to buy copies, charge a reading fee and do not offer compensation. Unethical publications usually cheat people by publishing their entry, along with others, and charging outrageous fees to see it in print.