For the statutory form, signature must be notarized, but you only need one witness. Two are suggested to best assure acceptance in other states or by out-of-state companies/parties. Non-statutory forms may not need to meet the same requirements, but they will not be as easily accepted.
I agree with attorney Repay's answer. Yes, the POA must be notarized and witnessed by at least one (1) individual. However, again as Mr. Repay notes, it is safest to have two witnesses so that it is accepted in other states.
Yes indeed, the Statutory Power of Attorney for Property needs to be Notarized and witnessed by at least two witnesses. The main reason for notarization of any recordable document, like a Warranty Deed OR a Power Of Attorney For Property, is to satisfy the requirements of the Illinois Conveyances Act. The Illinois Conveyances Act sets forth the technical requirements for a valid recordable document in Illinois.