That's no longer restricted to Microsoft apps, phone makers and mobile networks; any app can have a double-side tile now, and it can be a live tile that updates.
This is our preview based on very limited time with the new OS, which mostly looks at the new Start Screen and takes you through the features Microsoft is promising for Windows Phone 8.
We're hoping to score some more detailed time to properly look through and snap all the new functionality the Redmond group is hoping to bring, so stick around if you're itching to know more.

Start Screen

There are going to be a lot more features in Windows Phone 8 (some of which might well come to Windows Phone 7.8 as well – there's no way of knowing until we find out what they actually are).
Windows Phone 8
The only one Microsoft has shown in any detail is the new Start screen, which keeps the idea of live tiles that show you lots of information at a glance but gives you more options for the size of tiles and how you arrange them.
There's a new small tile size; you can fit four of those in the old Windows Phone 7 tile size.
The layout is completely flexible; press and hold the way you do on Windows Phone today and you can unpin a tile, drag it to a new position – or press the arrow that appears on the bottom of the tile to cycle through the small, large and medium sizes.
Even without the Zune-style 'trough' to remind you your other apps are on the right hand side, you only get two of what's now the medium tiles side by side, but there seven rows of small size tiles (or three and a half medium tiles) so you could cram in 28 small tiles if you wanted to.
More likely, you'll want a mix of small and medium tiles, with a couple of the 'double-wide' large tiles for apps that show a lot of information on a live tile.
If you make a tile smaller, the tiles next to it don't move over automatically; if you make it larger, it does push the other tiles out of the way, so you may have to move tiles a couple of tiles to get the layout you want.
You can use small tiles to offset medium tiles (at the side or above) so you get a staggered arrangement instead of just grouping them in the space of one medium tile.
The new Start screen gives you even more live information because you can fit so many more live tiles on. You get more control than ever over which tiles get more space and which have just enough room to show their icon or the number of text messages or missed calls.
You can still have the Windows Phone 7-size tiles in two rows if you want, but if you think using a whole tile for Settings or your Me tile when you already know what your profile picture looks like is pointless, the three new sizes and the underlying seven by eight layout give you much more flexibility. 

We're still waiting to find out more when it comes to what Windows Phone 8 will offer in terms of functionality, but here's a run down of what's been announced from our time at the launch:
Windows Phone 8
Dual core CPUs and HD screens are also now supported in Windows Phone 8, as well as being able to hot-swap microSD cards to install apps and media onto.
Windows Phone 8
Microsoft's Wallet Hub will allow you to use digital coupons, loyalty cards and pay for goods all from a central location, with third party apps supported too.
Windows Phone 8
Windows Phone 8 will use Internet Explorer 10 to allow even faster web browsing - although we hope the UI gets improved as well from the blocky efforts of before.
Windows Phone 8
'Proper' multi-tasking means you'll be able to get VOIP calls from the likes of Skype and turn by turn navigation in the background, while you play Draw Something.
Windows Phone 8
Although only a minor tweak from Windows Phone 7, the new OS gives a lot more room to the Start screen.
Windows Phone 8
Microsoft admitted it didn't perform as well as it would have liked with Windows Phone 7 in the enterprise sector, so has beefed up security and its app selection to have another crack at the lucrative market.
Windows Phone 8
Windows Phone 7 users can breathe a sigh of relief - they'll still be cared for by their brands and Microsoft for the foreseeable future.
Windows Phone 8
Windows Phone 8 in ice at the refreshments stand. Why not?

Early verdict

Windows Phone 8 is definitely a HUGE step forward for Microsoft. It's given itself (and its hardware partners) a great tool to use in the smartphone wars: being able to connect to Windows 8 tablets is a really smart move, as it presents a genuine reason to now own a tablet and a phone (rather than the iPad/iPhone situation, where they're just different-sized versions of one another).
However, the fact it's not launching until we're nearly in 2013 is a worry, as we'll have both Android 4.0 and iOS 6 entrenched in the market by then - and the handsets released will likely be competing with the iPhone 5, so will a slightly new interface be attractive enough to the casual buyer?
For the smartphone fan, WP8 ticks nearly all the boxes of missing features from the previous iteration; NFC, HD screens and multi-core support are all necessary and present.
It just remains to see what the hardware partners manage - give us some sublime handsets to play with, or make them dirt cheap like some of the Nokia Lumia range, and Microsoft will really be back in the smartphone business.

Source : techradar