A regular digital camera is not suited for continuous operation.
SecuritySurveillance Cameras are not our forte.

Here is a link to a Google search for:

surveillance cameras wireless outdoor

http://www.google.com/#hl=en&sclient=psy-ab&q=surveillance+cameras+wireless+outdoor&psj=1&oq=surveillance+cameras+wireless&aq=1&aqi=g5g-v2g-j3&aql=&gs_sm=1&gs_upl=12371l13806l1l20436l9l9l0l2l2l0l343l1857l2-6.1l7l0&gs_l=hp.1.1.0l5j0i15l2j0i18l3.12371l13806l1l20436l9l9l0l2l2l0l343l1857l2-6j1l7l0&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&fp=1361b6cc7752f590&biw=1440&bih=701

I suggest you start looking there.