Just grab some Clorox wipes for everything on the surface (except the monitor). For the monitor, you can get some cheap monitor screen wipes.
For inside the computer, don't worry about it, just use compressed air or an air compressor and blow out the dust.
I use this on everything from computer, car, audio, pets, and even inflated a boat once.
http://www.memoryexpress.com/Products/MX37982