According to MacGeneration, Apple is getting ready to launch Safari 5 and Mac OS X 10.6.4 at the WWDC. While 10.6.4 should be an update geared towards stability and compatibility improvements, the new version of Safari should carry a lot of new features, such as Reader.
As you can see from the screenshots below, the Reader functionality should be similar to what Instapaper already does: extracting text from an article and render it in a clutter free page. Other improvements should include a 25% faster Javascript execution, improved HTML5 support and new development tools.
[via 9to5mac]