The easiest way is to use Time Machine. I recently upgraded my MBP to a 7200RPM 500GB HDD and that is what I did. I made sure and backed up with TM prior to the HDD swap. Then once the new one was in, I loaded OS/X from the install DVD and then used the Time Machine transfer to move all my applications, preferences and files back over. It took about an hour from the time I put the install disc in until it was ready for use again with all my stuff.