I'm not into sports but when you talk about boxing (Pacquiao), I can immediately drop down everything and watch the fight. I have even watched Manny's fight with dela Hoya in Cinema. These days, especially in the Philippines, boxing is synonymous to Manny Pacquaio. At bakit naman hindi? =)
Anyways, if you are looking for a source to be updated on the upcoming PacMan boxing event on May 7, here's one source I can recommend - Pacquaio vs. Mosley Fight. I think they'll post there information about live streaming. They also feature there previous Pacquaio fights.