I want to subdivide a plane in 6 pieces and then cut and split the subdivision as separate and individual planes (without being linked to eachother). Just like in the image. Easy way to do this?
Numerous ways
Do you want each plane to be a separate object or just one single object.
For separate objects this is one way http://screencast.com/t/mJsy0R6P
If you want just one object you could just join them back together again.
Subdivide, select half of the faces vertically, hit Y and G .1 on axis you need. Repeat with upper and lower faces.
That will still be one object.