Hello,
i am new here. i am doing a project on dual axis automatic solar tracker using LDR. please favour me for the project. i am using arduino clone atmega328p.
Go with the sun position calculation code, do a forum search and you'll find it.
People have already also started many threads on this topic - go have a read of them too 
It's easy enough.
Some kind of motors to move the device which needs the sun (what motors depends on the type and weight of device) and some kind of position sensing on the two axes. Then you need some kind of driver circuitry for the motors and the arduino can do the rest with the sun position code - map the position values to what the motor driver requires and you're done
As I say, have a read then come back with any specific questions you happen to have.
Mowcius
Actually i am not doing the fixed algorithm tracking...i am trying to do the dynamic tracking by sensing the intensity using photo diods/LDR. I am using DC Wiper motor (2 pices) for horizontal and vertical movement. i also think to add datalogger herewith...i am confused with circuit for motor driving. Any idea about datalogger, i have 24c32a eeprom.