It pretty much goes without saying that a lot of us are (or already have) plan on dropping several hundred dollars later this summer and fall on the latest Windows phone, be it from Samsung, HTC, whomever.

But before you shell out your hard-earned cash and wait patiently for the release of Windows Mobile 6.5, a word of warning. Big things are afoot with Windows Mobile 7, and the two may not play nicely together.

More on that, after the break.

We've written numerous times that Windows Mobile 6.5 is more of a reskinning of WM6.0 than anything else, and we still expect that to be true. WM6.0, 6.1 and 6.5 are all built on the same version of WinCE.

Things will change with Windows Mobile 7. We've learned that WM7 will be based on WinCE 7, codenamed Chelan. Because of that, don't expect older devices won't be able to run Windows Mobile 7.

We repeat: A phone you buy now likely won't be able to run Windows Mobile 7. We'll be repeating this over and over in the coming weeks, so don't come crying to us next year.

What else have we learned? There is, in fact, an interim build. (And judging by the leaked builds we've seen since WM6.5 went gold, that's fairly obvious.) Windows Mobile 6.51 should be finished before the holiday rush. We've heard it'll be available for the AT&T version of the Touch Pro 2, but no telling if that's exclusive (and the folks at XDA Developers likely will make any exclusivity a moot point anyway).

So what will run Windows Mobile 7? To answer that, we have to look to the future. First off, phones that have the Qualcomm 8xxx series processors — that'd be Snapdragon — are expected to be upgradable to Windows Mobile 7. Current phones using Qualcomm 7200 or 7600 series processors won't. That's also in line with the rumored specs we'd seen earlier.

One phone we're pretty sure will meet those criteria is the HTC Firestone (also known as the Star). Another that we're hearing about is the Superstar, which is said to be the Firestone (seen here at right) with a keyboard. So, basically, we're probably looking at the next generation of the Touch Diamond and Touch Pro family.

So what to take away from all this? First and foremost, this is all totally unofficial stuff, and anything can happen. But the technical material makes sense. Second, we all need to prepare ourselves for not being able to upgrade most Windows Mobile 6.x phones to WM7.

Does that mean you should wait to buy a new phone? Well, that's totally a personal decision. It's probably a safe bet that while we may see Windows Mobile 7 announced early in 2010, it'd probably be this time next year before we get it on any devices. So Windows Mobile 6.5 should have a good bit of shelf life. We plan on making the most of it.