1. A telephony-based messaging system application stored on a computer readable medium for use by a particular customer, comprising: a module comprising call flow functions, code and a customization list; wherein the customization list comprises a table with a list of names and a modifiable list of corresponding DTMF signal identifiers, whereby the particular customer is permitted to change the mapping between caller-entered DTMF signals and the corresponding actions taken by the messaging system by modifying the list of DTMF signal identifiers.