Yes, flOw's coming to the PSP. No, it's not coming in January. In case you hadn't put that one together yourself. Instead, Sony have announced today that the game's due on March 6, and will be available for download through the PC/PSP PlayStation Store. Developers SuperVillian say they've been able to "reconstruct and faithfully preserve the unique experience of flOw on Sony's premier handheld device", but whether that means this is a direct port of the PS3 version or something new, I don't know, since they both look the same to me.
Coming to PSP: Go with the flOw [PlayStation Blog]