The jQuery team recently announced the release of version 1.6. This latest version boosts performance as the team has rewritten the way jQuery handles HTML attributes. Event Handlers now perform better, so do animations, with the introduction of a timer that can sync multiple animations to the same timer interval. There are many bug fixes as well.
There are some huge changes in the behavior of .val and .attr to support performance. For manipulating properties, two new methods, .prop() and removeProp() have also been added.
Learn more on the API changes over here.
Here are some links to download/reference jQuery from:
Overall I am very excited about this release! Watch out for upcoming posts which will detail these changes.