I find SparkNotes to be quite helpful.

http://www.sparknotes.com/

There’s no one online workshop that suits everyone. You’ll need to look around and get a feel for what suits your style of writing and critique. Many sites are heavily postmodernist and will slam anything that isn’t cryptic. Some sites focus on formed poetry and will slice your meter to pieces if you post free verse. Some encourage the lyric… the workshop must suit the poet. I’d recommend checking out a few of the older crit boards – visit the IBPC website and look at the list of participating boards. Browse and get a feel for what’s considered “good” on each of these workshops. Follow the links you find on these boards to other sites. Don’t worry too much about losing rights to your work. Anything you write is protected by copyright – whether it’s public or private. Your only concern should be the archive policy of the workshop (some magazines consider workshops with permanent archiving as “prior publication.”) I post all of my finished poetry on my blog. Poetry has no monetary value (unless you’re selling lousy anthologies to the vain and naive.) The only advantage to print publication is to earn yourself a teaching position somewhere. If you have no desire to teach, consider sharing your work in an online zine or blog. Good luck!