AP style says the first; some English teachers will insist on the second. If you're writing for a news publication and don't have any info to the contrary, go with the first.
Under AP style, you only use the comma before the last item in a list in cases where it's necessary to avoid confusion. Comes up a lot when individual components of the list involve the word "and" themselves.
* He had eggs, toast and orange juice.
* Over the day he had bacon and eggs, peanut butter and jelly, and toast.