Xfiles is an interactive utility for comparing and merging one file tree with another over a network. It supports freeform work on several machines (no need to keep track of what files are changed on which machine). Xfiles can also be used as a cross-validating disk<->disk backup strategy.
LazySync is a file-synchronization program written for handheld devices using the SavaJeXE Java operating system. It attempts to offer similar functionality to HotSync and ActiveSync of the Palm and CE platforms, and supports synchronization via an existing TCP/IP network connection between handheld and host.