We've waited—and, let’s face it, whined—but now it’s here: Windows Phone 7.8, which provides the new Windows Phone 8 Start screen capabilities to your Windows Phone 7.5 handset, is being released today as previously rumored.

(I’d heard nothing about this release from my own sources.)

Microsoft is touting the release of Windows Phone 7.8 from the Windows Phone web site. According to the firm, this update adds the following new features to your Windows Phone 7.5-based handset:

Start screen. With Windows Phone 7.8, you gain the single best new Windows Phone 8 feature: The new Start screen with support for three tile sizes: Small, large, and wide.

More theme colors. As with Windows Phone 8, you also get 20 accent colors, up from the 10 provided in Windows Phone 7.x.

Lock screen. While Windows Phone 7.8 doesn’t pick up the highly configurable new Windows Phone 8 lock screen capabilities, it does get one new feature, your choice of a dynamic new lock screen image each day from Bing.

That’s not too shabby. But something tells me this will be the last semi-major update Windows Phone 7.x users see. I’m also curious about whether everyone is getting this update immediately. I don’t see it yet on my AT&T-based Nokia Lumia 900, for example. (You still need to use the Zune PC software to check for this and other updates.) No word yet from the Windows Phone team.

Update: Nokia has posted a Software Update for Nokia Lumia with Windows Phone 7.8 page with some good info too.