No, I haven't really experimented much with that. I'll give it a go when I have time, but Rhythmbox gets halfway there... almost... It puts MP3s in the MUSIC folder, but it creates a folder called PSP in there and then a folder called MUSIC in there, so music actually goes into /MUSIC/PSP/MUSIC/(artist)/(album), while it should be /MUSIC/(artist, album).
There has been a bug filed about this, so hopefully it will be fixed soon.
And I can't actually get my PSP to show up in AmaroK, so you could try, but you might need to fiddle around a bit.