For TechDays – see:
Basically, this is a 24-hour event where there are over 70 1-hour sessions that will be available live or via download, after. There are 22 sessions in english. See:
and filter by English to see all the sessions that are available.
Also remember that there are lots of other webcast/video resources available too. You should regularly check:
Upcoming, live webcasts (typically 1 hour, during lunch, free):
Recorded, past webcasts of the live webcasts, above:
Channel9 – repository of many, many videos on all things related to .NET development:
For MIX09 – see:
Microsoft is going to make all the session videos freely available from the MIX09 conference that is going on right now. PLEASE NOTE: Not all the videos are available yet and may take up to 48 to become available.