[Update 3/15/2011] - IE 9 shipped yesterday and Infragistics is going to continue testing with IE 9 RTM bits and will ship service release next month for 10.1, 10.2 & 10.3 as mentioned below. There is also a slight change in the 11.1 release date, and it is now due to release early May.
Last week, IE 9 was shipped as a release candidate, which is expected to RTM at MIX this April. With the IE 9 release candidate, Infragistics started initial testing of the entire ASP.NET toolset against IE 9 and is projecting the 11.1 release time to be fully compatible with the latest IE 9 bits. The 11.1 release is expected to be ready by early April. Not only will the 11.1 release be fully compatible and supported against IE 9, but the support will be extended all the way back to the 10.1 volume release. It means that if you are using 10.1 or above, you can download the service release in April and be fully compatible with IE 9. Also, the entire toolset will be tested and supported with IE 9 from 10.1 & up, including the classic ASP.NET controls. Please check out this blog post to learn more about the ASP.NET product changes that were announced last year.
If you would like to participate in testing, please report any issues you find to our support team, so that we can verify it fixed when we publish the service release. if you run into any issues with any of the controls or have any questions, feel free to send me an email at firstname.lastname@example.org