Can anyone tell me some usefull online tutorials besides the one on php.net?
You could source for books at your local library, and of course phpbuilder.com itself has a number of articles.
How should I get started? What do I need? What do I need to configure? I know I will probably need php and mysql, but how do I configure all these things?
What tools you need of course depend on what features you require.
Check if your host provides PHP and some database support, e.g. mysql as you mentioned.
If you're hosting on your own comp, then exact instructions depends on your OS, but the PHP Manual probably would have some info.
Can I edit php with frontpage? How to enable this? If not, what editor should I use?
I dont use frontpage.
I suggest using a text editor, such as Win32Pad