Some hours of wrestling with pMachine's slightly weird db schema, and some debugging later, I got this converter done.
To convert a blog with it, you first need to install WordPress from CVS, then edit the file to put your pMachine database info, then load that file (rename it as .php and put it in your wp-admin directory) in your browser.
The conversion could take some time (a dozen seconds for a huge blog), depending on your blog's number of entries/comments.
What it does:
- converts a pMachine 2.3 blog's entries, categories, users, and comments (and trackbacks and pingbacks) to WordPress 1.2-alpha (cvs)
- users are converted with level 0, so you'll have to log in as admin to raise their levels
- 'closed' entries are converted as 'draft' entries
- preferences that have a WP equivalent are converted
What it still lacks:
- an actual interface, like the one used for other importers
- a way to translate pMachine users' levels to their closest WP equivalents (need info)
- some more testing :)
- it was done from a free version of pMachine 2.3, so I'm not sure of how well it should work with the multiweblogs (not free) version, though there is a blog id variable that you can set to choose the blog to convert