Just hit Alt+Shift+V in Firefox inside your Wordpress post screen. You will see an advanced toolbar popup below that standard HTML formatting options.

Works like a charm

via [just some]

CodeSnippet WordPress plugin version 2.0 released.

Whatâ??????s new:
- Tested and supported with the new WordPress 2.0
- Upgraded GeSHi code highlighning engine

See plugin page for information and downloads.