Art-Net is a protocol for sending DMX data over IP networks. Kosada's Quartz Composer arm (codename Kineme) just released a patch to allow the use of Art-Net to send/receive data from/to Quartz Composer. Kineme Art-Net Tools actually involves two distinct patches for interacting with Art-Net devices, one to send and one to receive.

See the full Kineme Art-Net Tools profile for specs, video, download link, etc.