Your Mac can already stop unwanted access out of the box. Sometimes it is desirable, however, to know when someone tries to circumvent these measures. This is where Watchmac comes into play: Watchmac monitors your Mac for possible infringements.

Watchmac is equipped with a full array of versatile sensors detecting all kinds of unauthorized use of your Mac. These sensors leverage the powerful technologies built into Apple’s latest and greatest products – but Watchmac also works on any older Mac running Leopard.

Not only does Watchmac record and warn about infrignements locally – you can even have an alert email sent to you. So if your Mac gets stolen you can react immediately.

Limitations: 15-day trial

Requirements:
OS X 10.6-10.8
For taking pictures: Integrated or external iSight (works with MacBook, MacBook Air and MacBook Pro, as well as with iMac).
Screen unlock authentication can be monitored on Mac OS X 10.6 (Snow Leopard) and 10.7 (Lion) when having Watchmac lock the screen.
For sudden motion detection, a mobile Mac with a sudden motion sensor is required. This includes MacBook, MacBook Air (Early 2008–Mid 2009 only), MacBook Pro or PowerBook G4 (Early 2005) and iBook (Mid 2005) models with a hard disk.
Power sensors only work on portable Macs. Power cord unplugging can only be noticed when the battery is installed. Battery removal can only be monitored on portable Macs with a user-replaceable battery.
Intel

Also available is:
Universal Binary version 1.6.4 for OS X 10.5