add this to /etc/apt/sources.list (replace the mirror with one next to you if you want):
deb ftp://ftp.de.debian.org/debian/ unstable main non-free contrib
deb-src ftp://ftp.de.debian.org/debian/ unstable main non-free contrib
replace 'etch' by 'testing' in all other lines
add this to /etc/apt/apt.conf.d/01local (the name of the file does not matter, as long as it's in the same directory),
or add it to /etc/apt/apt.conf - whatever you prefer:
APT::Default-Release "testing";
then run this:
apt-get update
apt-get -t unstable install wine
probably install one of those packages , too:
libwine
libwine-alsa
libwine-capi
libwine-cms
libwine-gl
libwine-gphoto2
libwine-jack
libwine-print
libwine-sane
libwine-twain
wine
wine-doc
wine-utils