i spent a good three hours trying to get a working combo of various versions of xulrunner and fennec to play nice...installed every version of fennec...
my experience was - completely flippin unusable.
couldnt even load google. curious how others did it.
here's where you can get at the .debs:

ftp://ftp.mozilla.org/pub/mobile/dis.../binary-armel/
and theres a minefield deb nearby, look in /extras