The Woman resembling Homer is a unnamed female who resembles Homer. It is obvious to tell that she resembles Homer by the five o' clock shadow, the overbite, and the head. Her voice is a lot like Homer's, but more higher, like a woman's.
When Homer forgets to pick up Bart from soccer practice, Bart spots a pink sedan near him that looks like the same car that Homer drives in. This wasn't Homer's car, however, and it was just a doppelgänger of the car driven by this woman who resembles Homer. As she is driving, she sings.