Version 3.0.4 of WordPress it’s available, through the update page in your control panel. It is a minor release but a very important update because it fixes a core security bug in the KSES HTML sanitation library that affects all versions of WordPress prior to 3.0.4.
If you manage an AlterSite:
Login in the control panel,
click on Publish > Install blog, fourm, gallery, portal
and then on Upgrade.
If you own an AlterBlog, after logging in to your control panel, click on AlterBlog > UpdateBlog