BackupPC is a fast, enterprise-grade backup system. It provides
a web-based user interface. It supports several platforms (Unix-like,
Windows, MacOSX) to backup to a disk-based storage.

No client-side software is necessary, as the BackupPC server uses
several protocols (smb, rsync, tar and ftp) native to the client OS.

File-level deduplication combined with optional compression minimizes
the disk space needed to store the backups and disk I/O and enables
synthetic backups to reduce network traffic.

BackupPC is not a block-level backup system but performs file-based
backup and restore. Thus it is not suitable for backup of disk
images or raw disk partitions.

BackupPC supports laptop environments with clients on dynamic
IP addresses (DHCP) not always connected to the network.

WWW: http://backuppc.sourceforge.net/