``Piper can be looked at in two ways: as a distributed scripting or programming language, and as a distributed bioinformatics collaboration tool. In the Piper paradigm everything is a node, certain nodes input and output data, every node has an Internet address, and nodes can be linked to define relationships, procedural steps and data flow. A node might represent an online database, for example. Each node has a Graphical User Interface (GUI) defined in XML. The interface has XML descriptions and some widgets. In bioinformatics, for example, a user might have a molecule widget to work with. With the Pied/Piper User Interface (Pied/Piper UI), the user has access to a Peer-To-Peer graphical scripting language (or if low level objects are linked, a graphical programming language). Piper is licensed under the GNU Lesser General Public License (LGPL).''

URL

http://www.oreillynet.com/pub/d/454

Piper is also mentioned along with The Open Lab:
http://www.oreillynet.com/pub/d/455