IE7 is finally here.
Check out the IE7 team blog.
There are a number of issues you have to check concerning this new browser, I highly recommend going to the link in this post to make sure your web applications are ready.
I personally tested IE7 on my PC and it is working great, and I so far the issues I’ve seen are relatively minor. I think the major issue will be layout support, but I am sure the IE7 team is hard at work on this issue.