Currently, the only integrated push is tapestry-cometd. Howard has mentioned a few times that he'd like to include a push implementation in tapestry core but that hasn't happened yet.
As has been mentioned, there's nothing stopping you from using Atmosphere and Tapestry side by side. If you declare the Atmosphere servlet (filter?) outside of tapestry (ie in web. xml) you will need to tell tapestry to ignore atmosphere URL's http://tapestry.apache.org/configuration.html#Configuration-ConfiguringIgnoredPaths Or, you can have tapestry manage the atmosphere servlet in the same way as I mentioned tapestry-cometd does.
