I am also still waiting to hear from USC. I applied for MS EE, Fall 2013 and still no decision. My portion of the application was submitted on Nov 1, 2012. My last letter of recommendation was submitted Jan 3, 2013. I called today to inquire on the status. I tried to press them for more info on the timeframe for a decision, but they would only give a categorical statement that the decision process will not finish until June 30 (!). Here is a copy of the email follow up they sent me.
This is extremely frustrating and disappointing. USC is my first choice. I have admission offers from other schools, but they want a response from me by today.