Yeah it's easy enough, there is a great DIY in the DIY section of the site, that's what it's there for.
My question is why do you mention rear only? Your front pads will undoubtedly wear out faster than your rears.
BTW, the sensor is pretty easy to tell as to whether or not it needs to be changed. There is one for the front and one for the back, and are coated with a ceramic type of coating. When it wears down, it sets off the warning light. If it's worn, change it. I bought front and rears, when doing mine, the rear didn't need it, so I took it back to my mechanic and swapped it for an oil filter :wink