XDCC-Fetch, written entirely in Ruby, is an intuitive, no-nonsense tool for searching, collecting and downloading XDCC announcements within IRC channels. XDCC-Fetch is released under the BSD license and available for free.
Avarice is a free program that allows you to download just about anything. Based on Bottler, Avarice is a fully-skinnable multi-server IRC client that allows for simplified XDCC access.