This has been asked a million times and the answer is:
Yes, but it will most likely kill the performance of your mouse. The tracking eyes are made cheaply and only pick up a narrow spectrum of light. Blue light is on a completely different spectral range and won't work as well with 80% of optical mice.
My advice is to simply add an LED instead of replacing the red one. Either by wiring directly from the 5v+ on the USB connection or by adding one parallel do the red LED.
I switched to a blue LED with my logitech iFeel over a year ago and I've never had any troubles!
Radioshack 5mm Blue LED
Forward Voltage: 3.7 typ, 4.5 max
Forward Current: 20mA typ, 30mA max
Luminous intensity(brightness): 2600 mcd
Radioshack part # 276-316
All you have to do is take out the screws, remove the covering(take care to remember where everything went!!), de-solder the LED contacts(remember which way the fat fin inside the LED was facing), remove the LED from the clear plastic lens, replace it with the new one, cut off the bottom wires, and solder it back in place.
Note! Soldering is pretty tough with machine soldered boards, so be careful! It helps to have a clamp or have someone to hold things for you, because you really need 3 hands to do the job properly