This powerpoint is a thorough, but not overwhelming, introduction to the Odyssey, Greek epic poetry, and Ancient Greek culture as we know it from this literature.
The Trojan War is explained, common terms for epics like nostos and arete are covered, Homer is introduced, etc. Odyssey is required reading at some point for students in the 7th-9th grade range, but it's a pity to throw them into the second epic of a two-parter.
I highly recommend accompanying this powerpoint with Bulfinch's condensed version of the Iliad. It's only a few pages and students will get a useful summary that will help them understand characters like Menelaus and Achilles when they appear in the Odyssey.