Free XML Services for Cisco IP Phones
Berbee, a Cisco Partner, has several free apps such as stock tickers and Weather updates.
http://www.berbee.com/public/berbeesoftware/XMLFree.aspx
To Configure it for CME or the UC520 Check this link
http://uc500.com/custom-xml-phone-services-uc500-and-cisco-unified-call-manager-express