Disclaimer: I work for a company that manufacturers On Hold equipment

When your callers are on hold, you have a captive audience. Lots of people sell a service to provide you profesionally mixed music (licensed) and marketing messages promoting your business. Just google for Music or Messages on hold, you will find lots of providers.

I think its a nice touch and projects a professional image.

Fyi, I covered some of these topics:

http://theory.whirlycott.com/~phil/antispam/rbl- ba d/rbl-bad.html#geopolitics
http://theory.whirlyco tt.com/~phil/antispam/rbl-ba d/rbl-bad.html#collateral