There are, of course, quite a few parrallel stories in the Odyssey and the Aeneid... Like the story of the Cyclopse, for example. A lot of "The Wanderings" is blatant Odyssey homage.
A few more general comparisions are:
- the importance of fate and destiny [the Aeneid is driven by fate, but the Odyssey has only the occasional reference]
- the portrayal of women [women in the Odyssey are very pro-active, and Penelope remains a model wife... But Dido breaks her tie to her desceased husband, and Aeneas' bride-to-be in Italy doesn't say a word]
- the portrayal of the gods [consider how more involved the gods are in the Aeneid]
- ideals of heroism [Odysseus is a trickster, Homeric heroes have a tendancy to be gung-ho, but Aeneas, as he matures, becomes more diplomatic]
- the father/son relationship....
...and well, there are tonnes! :-)