This
CNET article is ostensibly about Cisco's color VOIP phone, but tucked in at then end is a bit of interesting information:
Like most VoIP phones, the 7970G will also perform Internet functions such as searching a database for work orders. It does so by running programs written in an emerging software language called XML (Extensible Markup Language) that's used to share data over networks.
Also Tuesday, Cisco said it will extend XML capabilities to its 7905G and 7912G VoIP phones by the end of the year. The phones are available now, selling for $135 and $165 respectively.