Unlike the January CTP of WinFX that didn't include any updates to WPF, the Feburary CTP that we released this morning certainly does. Perhaps the most noticable improvements relate to performance. If you're doing WPF development, you'll want this.
If you have a prior version of WinFX installed on your computer, be sure to follow the uninstall procedures.
Last, if you're a MSDN subscriber, you can download the Windows Vista February CTP via MSDN Subscriptions.
Update: If you're interested in the status of Expression Interactive Designer and how it relates to the February CTP, see the post on the Expression team blog.
In case you haven't heard , the WinFX February CTP has been released. If you haven't downloaded it yet,