I know C-Span typically broadcasts the NASA TV feed during Shuttle launches. Can you convince them to broadcast DC in its place?
Also, looking farther down the schedule, I see that STS-125 is scheduled for May 12th and STS-127 is scheduled for launch (to the ISS) two days later. Wasn't the deal that another Shuttle had to hang out on the launch pad while STS-125 was servicing Hubble?