Nothing much has been said about what is including in iPhone software v1.0.2. The iPhone Software information window merely showing that the latest version of software includes bug fixes and supersedes all previous versions.
As the update will restore the firmware, so make sure you backup your precious photos taken with iPhone camera and other files before performing the software update. Else the pictures and other information may be lost and wiped off from the phone. And iPhone software v1.0.2 also validates the current iPhone software. Thus if you have installed any hacks, a complete restore is required and this will clean up all hacked functions and make iPhone backs to original square one. But you can always install back the hacked features.
To upgrade to iPhone software version 1.0.2, simply connect iPhone to computer and run iTunes. iTunes should automatically offers update confirmation box. Else, select iPhone in the Source pane and click the Summary tab, then click “Check for Update.”
Update: iPhone Software version 1.1.1 available for download.