DropCopy makes it easy to share files and folders among multiple Macs on your LAN using Apple's Bonjour technology. Drag your files from the Finder to a drop zone containing a list with destinations (see screenshot), and then drop it at the destination of choice. This list disappears conveniently when you aren't dragging files over it. Clipboard sharing and short text messaging are also supported.
DropCopy is available for free to individual users (upto 3 machines on a network), and a suggested shareware cost of $25 for a complete site license. DropCopy mobile can also be used to transfer files to your iPhone.