The official IE Blog announced that IE7 Beta 2 is now released. This is a quote from their blog:
We acted on a lot of the feedback and bug reports from the previous public releases. In particular, I feel good about changes we made based on reports from web developers around some CSS behaviors, application compatibility feedback, reliability data (yes, we do analyze the information that comes when you click “Send Error Report”), and user experience feedback. People on the team will post additional details about changes over the next few days.