Simple and short explanation: Revised form of nikon D40.
It is heavier, have 11 AF points (D40 has had 3 only) , CMOS sensor, higher resolution with 12.0 MP , video and a foldable LCD screen (finally !)
But the price is heavier too...
But if you can not afford a D90, this may be a better solution. But do no forget, D5000 can work with DX / AF-S lenses only. It has no internal motor like D90.
Technical specs :
12.0 MP, DX format CMOS Sensor, Live View, ISO200-3200 or 100 (Lo1.0)-6.400 (Hi1.0), 4 fps, 2.7" 230.000 dots LCD screen, D-Movie Mode, 420 Segment RGM colour matrix, ultrasonic self cleaning sensor,11 point AF Area. min 1/4000 sec to max 30 sec (bulb also available)
Recommendations:
Wait... Wait for a while for the price goes down to reasonable levels. If you need to buy a DSLR urgently, add 20% more and buy a D90.
If you have a D40 and waiting for an upgrade, this may be your answer, but wait for several months for the price compensation..
If you have older Nikon lenses (AF lenses), you must go with D90. But if you have DX lenses , it is not a deal at all.
June 2010 >
I believe that the D5000 is one of the best entry level kit for enthusiastic beginners. Only be careful about the low resolution movie compared to rival Canon 500D. But, as this is a photo camera, please do not confuse with these marketing tricks of the rivals and buy a photo camera.