Sony has mentioned in the past that its new handheld and its upcoming console would get along together, but it wasn't until the big unveiling of the PS3 that concrete details have been available on how this will come together.
In its PS3 unveiling, SCE announced that the PlayStation 3 would have support for USB 2.0, Wi-Fi, Bluetooth and online networking. Those first two are the biggest concerns for PSP owners, as Sony officially confirmed that the Wi-Fi configuration of the PS3 would allow the PSP to wirelessly connect with the home console. No wires, no connectors, no muss, no fuss. Of course, the PSP also has outlets for the USB 2.0, which might allow for corded connections as well as wireless, if necessary.
PSP won't just be used for wireless file transfers -- according to the official specs for the system, the PSP can be used as a controller for the console. Whether PSP will be used as a PS3 controller much is up to developers -- the GBA and GameCube got along great together, and the PSP obviously has a lot more capable hardware to do interesting things than that duo. Whether PS3 developers enjoy that gimmick of a system with a full-color screen or else decide to stick to the more complicated PS3 controller configuration is a matter we will find out in time.