From good old wiki
You may want to disable the
automatic software updates checks
that occur upon internet connection,
in order to consume less bandwidth
when using 2G/3G connections. You
can do so by editing the gconf file
found in /var/lib/gconf/apps/hildon/
update-notifier and changing the
check interval from 1440(24 hours) to
a much larger value. The value must
not exceed 2,147,483,647:
gconftool -s --type int /apps/hildon/
update-notifier/check_interval NEW_
VALUE