I'd have to look into the samba site, i have the game but haven't checked out. anyway even if it's not up, they will be up at the SegaFans website soon, about all other games downloads (including the unreleased Sonic Adventure 2 files) are up. i think the only ones not up are PSOv2 and Samba De Amigo, this however is only counting US games, there are some PAL and Japanese, but not much.
Oops, i didn't look at the link, what i said above stays true for the US release, but for ver. 2000 thats the only way to go if you want it done right, however at gamefaqs.com you can download a file (i think it's a hack or cheat) that will unlock everything even the download songs.