If Carthage is able to pull a victory in the first one (which really nearly happened anyway), its likely that Carthage would take full control over Sicily. I'm unsure if they would outright annex the eastern Greek city states, but would certainly put governors over them that worked for Carthagian interests (this had long been a goal of Carthage and one of their attempts actually caused them to ally with Rome at one point in the past). I would also suspect that the Roman alliance system would be dissolved, and a league of city states in southern Italy would be set up to counter Rome's influence in the region. Finally, I think its pretty likely that Carthage would force Rome to burn their navy and forbid them from establishing one ever again. This would leave all of Italy open to Carthagian raids and attacks should Rome try to reestablish itself.
I highly doubt that Carthage would attempt to annex any land in Italy proper; it would be too costly, have very little benefit, and goes against the precedent of previous Carthegian military victories.