I know where to get all the character songs.
It's gendou.com and you need to register first before you download.
It's really easy to sign up though.
http://gendou.com/amusic/?filter=card%20captor%20sakuraThis is the first page of songs, they have a second page too.
Just click on the next page at the bottom.
Here are the titles in case you don't know them.
Kero's song: Issho ni Utao
Meiling's song: Kocchi wo Muite
Touya's song: Kimi ga Ita Scene
Yukito's song: Jitensha ni Notte
Sakura's songs: Prism
Hitotsu Dake
Shiawase no Maho
Tomoyo's song: Watashi Dake no Movie Star
Syaoran's song: Kininaru Aitsu
Enjoy! :O)