You can do this using the regular interval monitoring option in
WebCam Monitor.
From Quick access, select the 'At regular intervals of:' option and put the time at 60 or 90 minutes.
If you want to capture only a single photo every hour then click on the 'Configure' button for the 'Take Photo' action and put value '1' in both the numeric text boxes.
Using the regular interval option allows you to increase the time interval between pictures or any other action you choose.