For Perl interfaces to MySQL, DBI installs fine but there's a bug in the system version of Perl that prevents going any further. Make the simple (ish) fix, then use cpan to install Bundle::Msql and choose the MySQL items and not the Msql ones. Or at least: you could do otherwise, but for some reason (despite loads of errors printed on screen) that was the only way I got it all to work.
I was going to say iChat was finally AppleScriptable, but it looks like although all the stubs are there, the return values aren't useful (but I may be doing something wrong).
This feels like a good release, even if there are a whole load of scrappy UI decisions. It's close enough to 10.2 that most of the weird hacks still work and there's not much more to learn. And it runs well on my aging iBook, which is a pleasant surprise.