Tomorrow's the day. After months and months of waiting after Windows Mobile 6.5 was announced at Mobile World Congress in Barcelona, Spain, Microsoft's work comes to fruition, with a massive worldwide launch of the new operating system, new phones, and new (or not so new) services from Microsoft.

We'll be there live in New York City for the whole shebang, so be sure to check in Tuesday morning. In the meantime, join us after the break for a brief primer of what we're expecting.

Windows Mobile 6.5

This one's kinda a Big Deal, folks. And at the same time, it's not. It's no great secret that updates to Windows Mobile are few and far between. Windows Mobile 6 has been long in the tooth for quite a while now, and we're anticipating a major overhaul with Windows Mobile 7. But in the meantime, there's Windows Mobile 6.5.

Windows Mobile 6.5 primarily is a Big Deal for those of you using touchscreen (Professional) devices. That's where you'll see the greatest difference in use over previous Windows Mobile experiences. There's a new Today Screen and a new Home Screen. Internet Explorer 6 is much improved over previous versions (though there's still plenty of room for improvement).

But when you get down to it (and this is something we've been aware of since 6.5's announcement), it's really just a reskinning of Windows Mobile 6.x. That said, we've seen plenty of newer (leaked) builds of Windows Mobile 6.5 that emphasize finger-friendliness even more, but we're not expecting to see those builds until a 6.5.1 release later this year or, more likely, early next year.

The bottom line: This is not a huge upgrade to Windows Mobile, but it is a major one, and worthy of celebration.

Windows Marketplace for Mobile

Finally, Microsoft is giving the tens of thousands of Windows Mobile apps a place to call home. Yes, there are (and have been) app stores available from the likes of Handango and Mobihand, among others, but none of them has the weight of Microsoft behind them. Enter Windows Marketplace for Mobile.

The Marketplace app will be built in to Windows Mobile 6.5 ROMs, which clears the major hurdle of getting people to it in the first place. There will be free apps. There will be paid apps. How many apps, initially? We don't know for sure. We've heard numbers in the hundreds, but nothing official. It can be browsed online as well as on your phone, and apps can be loaded from either place.

The Marketplace will be available immediately (or already, in the case of the AT&T Pure) for Windows Mobile 6.5 phones, and is officially expected on 6.0/6.1 phones in November. (Erm, and a little earlier if you go a different route.)

The bottom line: It's about time. We still have some questions — what happens with apps we've previously purchased outside of the Marketplace? — but we expect things to be worked out.

My Phone

Everything's all about the cloud these days. Microsoft's My Phone service has been in open beta for a while now. It'll sync your contacts, pictures, text messages, calendar, music, documents ... You get the idea. On Tuesday, it graduates to the big time.

We're expecting an increase in storage size (it's currently at 200MB), and the addition of services, including remote locate and wipe. My Phone is expected to have free and premium features.

The bottom line: Very cool, but it's a shame it works through your phone's Exchange connection.

Phones, phones and more phones

Having a new operating systems is great, but you've got to have new phones to put it on. The official list: AT&T, Bell Mobility, Sprint, TELUS and Verizon Wireless, and phone manufacturers HP, HTC Corp., LG Electronics, Samsung and Toshiba Corp.

If you've been around this site for more than 5 minutes, you're probably well aware of what's in store ... The HTC Touch Pro 2 and Touch Diamond 2. The new Omnia line. And that's naming a scant few. One big question that remains is if any older phones will receive official updates to Windows Mobile 6.5. That said, there are plenty of ways to, ahem, get the new OS on an older phone.

The bottom line: Sweet. Who doesn't love new hardware?

What else?

Like we said, our man Malatesta will be on hand Tuesday in New York City, glad-handing the Microsoft folks, watching the morning keynote and basically soaking it all in.

So what do you want to see? Let us know in the comments, or hit us up on Twitter.