The first thing you need to do in migrating from Serendipity to WordPress, is to move the post content. Luckily for all of us, at some point in time an importer was written (and shared). It has floated around the internet for a while and been updated a number of times. The version I used was verison 1.3, last updated by a German fellow. While his updates were good, I needed a little more out of it. Two pieces that were lacking were the handling of drafts vs published posts (John and I have a number of drafts, as has been previously mentioned) and the most important, matching up post id numbers. Without that one piece, you can’t move between the two platforms and maintain any links.
The first piece is easy, the second isn’t as much. WordPress doesn’t allow you to select your own post IDs during the post creation routine. Fortunately for you and me, there is a workaround, it involves a little bit of SQL, but anyone with the ability to READ and operate PHPMyAdmin (or command line MySQL), should be able to do this. So I’m proud to announce
Serendipity (S9Y) importer for WordPress 1.4.
Please READ the readme.txt file. It is short and contains all the instructions (and SQL) you need. If you follow the instructions properly, you should be able to import a fair sized blog (~1000 entries/comments) in less than 10 minutes.
Update 2013-07-13: The plugin has moved from Google Code to a new s9y-to-wp repo on GitHub. Pull requests are always welcome!