For some reason I hadn't been able to get any of the wysiwyg editor plugins in my serendipity install to work. It's been a minor annoyance, so I decided to figure it out tonight. Here are the steps:

1. Go to Configure Plugins and download/install the Xinha plugin. If you're lucky, it'll just work.

2. Download the Xinha package from the xinha website.
3. Drop the file you downloaded (Xinha_0.96beta2.tar.bz2 for example) in a folder of its own.
4. Run bunzip2 Xinha0.96beta2.tar.bz2 on the command line in that folder.
5. Then run: tar -xvf Xinha0.96beta2.tar

6. Copy the files extracted to your plugins folder at:/plugins/serendipity_event_xinha/
7. Refresh and hey - it actually works.

I don't know why had such issues with it before. I had uninstalled and reinstalled that plugin from the interface several times to no affect.

Good presentation from Jay Pipes about big mistakes you can make when developing with mySQL. I particularly like the point of not thinking in loops but in sets.