installing package from unstable

["Mathieu Malaterre" <mathieu.malaterre@gmail.com>]

Hello,

 I must be doing something wrong, but I cannot figure out what:

$ cat /etc/apt/sources.list | grep unstable
deb http://ftp.debian.org/debian/ unstable main contrib non-free

$ sudo apt-get update

$ sudo apt-get -t unstable install gcc-snapshot
Reading Package Lists... Done
Building Dependency Tree... Done
E: Couldn't find package gcc-snapshot

system: debian sarge

thanks,
--
Mathieu