Everybody has something to donate and you can plan your donation as volunteering. Volunteering does not mean only to fly overseas and spend your time at mountain villages. You can also donate your time as online from your chair and no need to go anywhere.
UN has launched an online volunteering project that matches people who are willing to volunteer and the organizations who need somebody who will assist them online. The system works through current announcements of organizations. You just need to register yourself and apply one of the open position.