How to change the work area title

In CRM 2007, when you click the work center in the left side, there is also a title on the work center page ,

for example, if you click the work center of Account Management, you will also see the "account management" on the title of this work page.

The problem I met now is I already change the title of the work center , but don't know how to change the title of work page.

Any one can give me some idea? Many thanks!