Of course, I know of the Victorian pneumatic tubes. But with today's technology would be very different: the pods would be electric and autonomous, and the pipes would be nothing else than enclosed rails. The routing would be performed by the pod itself in communication with the pipe, and the pods could use radar to avoid bumping into each other.
It would be a rather simple system, really: a closed pipe with a rough guide, with sensors and data exchange points every now and then and at junctions. The pods would not have to be very fast: 60km/h would be already a fantastic speed inside cities when the only stops are start and destination point. The pipes can be taken to individual buildings (shops, offices, houses), but there could also be public delivery and shipping points on each street/ block. The standard (small) size and shape of the pods (or of their internal container) means that they can be easily manipulated automatically: for example, collected and shipped on different transportation systems such as trucks or rails to reach distant or unconnected destinations, then reintroduced into the pipes system.
Elon, where are you? :)