the following is a list of applications recommended by idin.net. most of them are free and some of them are open source.
ip filtering:
peerblock (windows)
peerguardian 2 (mac)
bittorrent client:
utorrent (windows, mac, linux)
internet-based file synchronization:
live mesh (windows, mac)
drop box (windows, mac, linux, mobile)
reference management:
mendeley (windows, mac, linux)
statistical computing:
the r project (windows, mac, linux)
no response to “software”