Microsoft officially released the NoDo ("No Donuts") update for Windows Phone 7. This is the first major update to the platform that introduces many long-awaited features, like copy/paste capabilities, fixed camera switch bugs and major performance improvements related to application launch.
The newest build version is: 7.0.7390
Not all devices get the update at the same time. If there are no carrier restrictions, there is also the factor known as the propagation time - the period it takes to distribute the update package among various local content delivery networks. If you did not get an update yet and don't have a pre-release device, your only option right now is waiting.
This is certainly a milestone for the platform as a whole, however the update process is not perfect. It was announced that the update is currently only delivered to unbranded phones - devices that are not directly tied to a carrier (or, as those are commonly known, unlocked devices). Seems like for now major carriers took control of the current release (according to this page). T-Mobile Germany took it to an extreme and openly declared (according to this user and this one) that the NoDo update will be delivered to its users by the end of April. I am not entirely sure this is the best way to push the possible update when competitors are a bit faster delivery-wise.
Given the fact that the majority of devices "in the wild" are carrier-locked, the fact that the February update is in Scheduling and Testing stages for some people is simply frustrating for those who want to use their devices with the latest capabilities.
For more information on the update history (as well as for a list of improvements) you can visit this page.