Just posted on the SharePoint Team blog is a bunch of information and links to the newly released Infrastructure Updates for MOSS, WSS and Project Professional.
These updates include bug fixes, performance enhancements as well as new functionality and features around Search. According to the blog post, it is recommended that all customers install these updates to take advantage of the improvements immediately.
I will be doing some updates over the next few days on my own machines as well I am sure we will be patching our many development environments at work. I will post any personal findings and experiences as they become available.