It'll unlock new uses for PSP
We're fans of Sony's gleaming handheld, but there are so many PSP possibilities that haven't been properly explored. The launch of PS3 should help to change this. You'll be able to download PSone games (the GamesRadar coffers are already filling up for Resident Evil) and potentially PS2 titles onto your PS3, before zapping them over to a PSP to play them.
Or, with Remote Play, you can use your PS3 to hold all those big movie or music files, then stream them on your PSP. And hopefully in the future you'll be able to do this over the internet, wherever you like, not just via WiFi local connection around the house.
Finally, you can cut out all the annoyances of getting new PSP stuff off the internet and into your machine. Just visit the PS Network store, grab the PSP bits you want - like extra tracks or new levels - and zip 'em across to the handheld.