We English teachers aren’t supposed to care about such things anymore, but fug it: knowing something about the basics of poetic form will enrich your understanding of poetry. In other words, it will make poetry more pleasurable for you. It’s like taking a basic music appreciation class and then going back and listening to records you already dug. Scansion is like dancing: it is all about learning how to follow the beat.
With this fact in mind, some good English Dept. folks at the University of Virginia (which I believe is the school Mr. Jefferson founded after he got his degree at my alma mater, William & Mary) have launched a wonderful new website for poetry nerds to waste time on. It’s called “For Better of Verse” (yeah, I hope you like puns, too), and in addition to an excellent glossary of poetic terms (teachers take note), it has a very, very cool interactive prosody widget. Doesn’t that sound fun?! Trust me, it is, even if you don’t think you care or need to know about iambs.
Using various canonical lyrics as well as passages from longer works–and I mean really canonical: it’s heavy on people like Milton and the Romantics, with some Yeats thrown in–the site allows you to practice your ability to spot the accents (i.e. the metrical emphases) and other key formal features in lines of poetry. The site will even “grade” your efforts. Scansion is an imperfect technique, because it is often possible to place the accents in one line several different ways, and the whole deal might sound stuffy and academic at first, but trust me, this is like an addictive video game. Learning to scan “traditional” accentual poetry will in turn help you detect and savor the sonic features of “free verse”: once you can pick up the difference between, say, a trochee and an iamb, you will notice yourself paying more attention to things like internal rhyme, alliteration, and syllable counts, formal features which remain crucial to free verse, even though f.v. mostly dispenses with traditional meter. Scan away!