Illuminate printing area

looks nice :-)

Thanks. This was such an easy mod. I just bought an LED strip light kit off eBay. It has a 5050 LED chips. We just cut to length and stuck it in place (I printed two angle pieces so the tape had something to stick to when running from one side of the gantry to the other). The adhesive on the strip was poor so we just added clear packing tape so it's very secure and won't vibrate loose. Also we taped on the IR receiver.

A 13" mirror from Home Bargains at the back lets me see what's happening underneath the fan too...

That LED fan is great, but could I run the LED's off the fan power?

yes, I took 12V from the cooling fan line. not a problem

I am also looking to attach some lights on my mendel90, i am going to use this lights, they are very bright [hobbyking.com]
But i dont know how i need to power them

Those strip lights are the same as mine - they take 12V, which you can take from the bed cooling fan line or directly from the PSU (might require a bit of fiddling with the 12V lines that you crimped/soldered together originally) - using the cooling fan line allows you to switch the lights on and off via gcode.

If you want to control the lights through gcode and you are already using the bed cooling fan then you'll need to do a little more work.
I use the Panelolu2, which on top of the cool LCD screen and independent controls also gives me two switched 12V supplies which I use for my LEDs.

i' m also using the panelolu2, can i attach the cables of the led strips on the red connector plate of the P2 or can i attach then to the fan input on the melzi?

The Melzi adapter board for the Panelolu2 has two FETs labelled Transistor1 and Transistor2.
The white headers next to these are the 12V feeds that are switched by the FETs and are mapped to arduino pins 27 and 28.
To turn them on or off in gcode you can just issue the appropriate M42 command:

M42 S255 P27

Switches on pin 27

M42 S0 P27

Switches off pin 27

I just put these in the relevant places in my start and end gcode files.