This relatively cheap prized camera was introduced on July 30, 2009. It may be seen as the successor of the Nikon D40, of which more than 1 million were sold worldwide. It has the sensor of the Nikon D60 and many features of that camera and the Nikon D5000. The Nikon D3000 has a larger LCD screen at the back: 3 inch in stead of the 2.5 and 2.7 inch of the two mentioned 'brothers'.
Have a look at the matrix for technical specifications.