应该是不支持所有的ISP，俺刚开始用问过一次，后来都很顺畅，试一下介个吧

1. Go to http://espn.go.com/espn3/index 
2. Click on Watch Now. 
3. Select ATT from the ISP drop down menu. Click Continue. 
4. On the ATT login screen, select Sign Up Now. 
5. Follow instructions to create a NEW, FREE account. 
6. Go to http://espn.go.com/espn3/index 
7. Click on Watch Now. 
8. Select ATT from the ISP drop down menu. Click Continue. 
9. On the ATT login screen, and login to ATT with the account you just created. 
10. You now have access to ESPN3 video.

Good luck and tell us if this works！