Palm Treo 600 - Manual (Page 127)

Button settings :: 125
Setting default applications
Some applications look for other applications to handle data (for example, a mail
application might launch a browser when you choose a link in an email message).
1. Press Applications Launcher .
2. Choose the pick list in the upper right corner, then select All.
3. Choose the Prefs icon.
4. Choose the pick list in the upper-right corner, then select Default Apps.
5. Choose each pick list, then select the application you want to associate with that
function.