Scroll down a bit for a list of WP 2.3 tag plugins.
Tag: 2.3
WP 2.3 Related Posts « Extend › Plugins
sandbox-theme – Google Code
Looks like sandbox 1.0 (gold, baby!) includes tag-friendly markup for WP 2.3.
Page Category Plus – Stuff at Yellow Swordfish
WordPress 2.3 plugin to give pages categories.
Ryan Sholin 