Especially in the original trilogy, there are several plot points that imply that there is no faster-than-light communications in the Star Wars universe, other than using a hyperdrive-equipped ship to physically carry information from one place to another. For example:
Leia tries to physically take the Death Star plans to Alderaan. If there were a way to electronically transmit the information FTL you'd think they've have just done that, rather than hand-carry the stuff.
Leia has to go pick up Obi-Wan on Tatooine. Seems more complicated than sending him a note and/or wiring him some money for a ship.
Some potential counter examples:
Vader talking to the Emperor via video chat in ESB and RoTJ. Of course they could have just been close by, and indeed are during RoTJ.
Tarkin gets a report of a ship like the Falcon blasting out of Mos Eisley as they arrive. Seems like any comm would have had to travel very fast to beat them to the Death Star as Han and crew were in the Falcon.
So, is there any OT evidence of FTL communication? How is this supported or not by the rest of the canon?