[1]wget
(a)Wget. Download its src from http://ftp.gnu.org/pub/gnu/wget/ and install it.
(b)edit make.conf.
Sample:
FETCH_CMD=wget -c -t 1
DISABLE_SIZE=yes
(c)If need proxy. edit ~/.wgetrc like below:
http_proxy=proxy:ports ftp_proxy=proxy:ports

OR,(did not test) add belows to make.conf
FETCH_ENV=http_proxy=http://proxy:ports
FETCH_ENV=ftp_proxy=http://proxy:ports


[2]Prozilla
(a)Install it
(b)Edit make.conf:
FETCH_CMD=proz -s -k 6
DISABLE_SIZE=yes
FETCH_ENV=http_proxy=http://proxy:ports
FETCH_ENV=ftp_proxy=http://proxy:ports

From: http://www.freebsdchina.org/forum/viewtopic.php?t=25246