TclMML -- http://tclmml.sourceforge.netAuthor: Michael A. Cleverly Current version: 1.0b1 (10/28/02)
From the SF project home page:What is TclMML?TclMML is a Tcl package designed to make it easy to interface with the United States Postal Service's Mailing Online System  by using the XML-based Mail Management Language' interface.Coincidentally, much of the USPS MOL system is implemented using Tcl :-) , .An Overview of Mailing Online & the Mail Management Language"The USPS offers a convenient online hybrid mail service that allows a user to upload a document with a list of addresses, select various printing options and mailing options, pay via credit card, ACH and custom payment, then submit their request. The system optimizes their request, and sends the documents to various print sites strategically located throughout the country. This distributed printing is based on the ZIP Codes contained within their address list. This system is called Mailing Online (MOL). Typically all customer interaction is through various web pages that make up the user interface of the MOL system. However, there exists another method that allows the customer to use the system without going through the interactive web pages. This is accomplished by utilizing the 'Mail Management Language' (MML) that is an integral part of MOL."