Me too! Here's the comment from the blog (pulled directly, posted an hour ago):

"After seeing that my PHL-DUB flight was missing, I called them (US Airways) this morning and they told me that it was an error on the US Airways website. The agent confirmed that my tickets were still valid and they resent me the flight confirmation. After calling them, my PHL-DUB flight segment was back on the US Airways website. My original seat selection was gone for the PHL-DUB flight, but I was able to select them again."