By adding the following alias to .profile you can easily switch from the stock-scp to a resumable one:
alias scpresume="rsync --partial --progress --rsh=ssh"
It's then just a matter of using "scpresume" where I would use scp(1):
intellian% scpresume medahugefile.tar.gz remotehost:
This shouldn't incur too much overhead, but it sure makes large transfers much less painfull on a bad home-user uplink.