I tried the ActiveSync backup utility, and it was very, very slow.
It took around 45 minutes to backup my PPC internal memory data to my PC.
So I tried a different approach.
I created 4 folders on my SD card:
\Windows
\Program Files
\Root
\Registery
I then used GSFinder+ and just copy/pasted the contents of my main memory \Windows folder to my SD card \Windows folder, using a Select All command.
I did the same with \Program Files, and also with the few files in my root directory \My Mobile Device.
I then used freeware program PHM RegEdit to create a backup of the Registery.
Then I did a Hard Reset, and did the reverse of the above, and just copied files back from the SD card, back to their respective folders, and used RegEdit to restore my Registery from my backup.
When I ran ActiveSync, my \My Documents folder, and my Pocket Outlook data was restored back to Calendar, Contacts, etc.
Everything worked fine after I restored the data.
I also copied all of my above backup folders to my Desktop PC in case my SD card is damaged or lost.
So Sprite Backup is probably the best way to backup (as many people have mentioned).
The included Data Backup utility Gigi mentioned above, is probably the next best approach.
And my above process will work, as well.