Fire up your updaters, campers, because there's a prize inside -- in theory, anyway. iTunes 10.5.2 has appeared on the iTunes direct download page, but it's not yet showing up in Software Update, and the KB article covering the update is now 404ing.
Reader Chasapple also points out that the Apple security updates page is having a bit of an issue, too; it's not displaying. Dropping the trailing slash in the URL helps though. :)
Nevertheless, if you're going to download it now, 10.5.2 should be offering the following changes and improvements:
Several improvements for iTunes Match
Fixes a distortion problem playing/importing some CDs