Registration for the online event happening tomorrow (10 June) at 11AM EST can be found at RedHat.com. The site says it's about, "redefining the enterprise OS."
Most likely this press conference is about announcing (or the plans to) the release of Red Hat Enterprise Linux 7, which is looking fantastic and performing great. Its release candidate has been out since April and a public beta prior.
the latest Ubuntu Developer (Online) Summit.
Stay tuned for details tomorrow...