Is there a way to update many opportunity records at one time?

It is the beginning of the new year and the company would like to mark any opportunity that has not been modified within the last year as inactive.  Is there a way to do this within CRM On Demand?  Could a web service or something be written to do this?  It is something that they would like to do every year.

Message was edited by: user10790034 The below (Siebel CRM MOSC) is the only thing I am able to change to. When I search on CRM On Demand, it shows up, but is greyed out and I am not able to select it. And when I go to the CRM On Demand community, I cannot submit a question.