I use the Private Use Area a lot. Many of my fonts are available from links in the Gallery forum if you would like to have a look at one or more of them in FontCreator. First download a copy of the font to a folder on your computer and then open the font in FontCreator from there.
Views on Symbol fonts vary. Personally I rarely use them and I think I have only used them for tests to learn how to make them.
You might find it helpful to have a look through the following recent thread.
The following might be of use early on.
I cannot fully justify the following advice with theory, but I would advise that you use, while you are learning, only those Private Use Area codes that start with E and that you avoid using any which end in 00 or 40 or 80 or C0, just in case of problems. Some of it is theory based, some of it experience with the way that some software packages have previously assumed things about certain Private Use Area codepoints.
I hope that this helps.
William Overington
8 November 2007