The BlackBerry App World store went live on Wednesday, but what's it all about? Here are the main things you should know.

Everything is in $


That's right, at first everything will be priced in dollars even if you are accessing the App World from Canada or the UK. However after you've accessed the PayPal area of App World all the prices will then be displayed in your local currency. Interestingly while the dollar price is fixed, UK prices will fluctuate with the exchange rate that PayPal sets, suggesting that you could pay one price one day and a very different one the next.

You can't separate free from paid for


Unlike the iPhone App Store that lets you separate free and paid for apps you can't do that in App World at the moment. You're going to have to scroll through all the apps to see what's free and what you've got to pay for.

Developers will be able to charge you "in app"


It's a feature that's coming to the App Store on the iPhone, but developers creating apps for App World will be able to charge for app extras within the app. Shazam is already doing this. It is free to download, but to keep all the features you'll have to pay £5 via a link within the application. That link isn't linked to the PayPal App World payment page and therefore won't fluctuate.

It will work out your location and device


Kind of. App World will work out where the country your BlackBerry lives (i.e., the operator you are signed up with) and then serve you apps accordingly. Developers will be able to then say that they only want it to appear for UK customers. At the moment however most seem to be ticking the "global" button. The app will also work out what BlackBerry you have, meaning you won't be able to download touchscreen-enabled apps on your BlackBerry Bold. Likewise Storm users won't get applications that require the trackball.

You will be able to remove apps from your phone but still keep them


Within App World is an area called My World that allows you to see what apps you have downloaded. You'll be able to uninstall apps from your device without losing them completely. RIM says instead they will be stored within "the cloud" meaning you can ditch stuff if you've run out of space.

Only be able to store apps on internal memory


Whether you've got a 16GB microSD card in there or not, you'll only be able to store apps on your BlackBerry's internal memory, not ideal if you've already got plenty of pictures and music saved already. RIM say that they believe you should be able to get around 100 apps on the average device.

You can down load over the air


You aren't going to need to find a wireless hotspot to have to download the latest apps, however you will need to make sure you are on a good data plan if you don't want to rack up a large bill. Additionally if you aren't sporting a 3G connection downloading those apps will take time.

Featured apps


RIM will be offering users around 15 recommended apps for you to download, supposedly these aren't going to be paid for spaces but "editorially driven". No word however as to whether or not they will be based on what you've already downloaded or is relevant to you.

Top Downloads


The App World chart will be based on the most downloaded apps in your country in the last 24 hours. It's only updated once, however it will let you see what's good and what's not.

Customer reviews and ratings


Don't like something, love something else? The App World store will allow you to share the love or hate so others don't or do make the same decision. Judging by some of the comments already live it's a no holds barred affair already.

Pricing


Pricing for the apps could be completely different to what other mobile phone users are paying elsewhere. Pocketgamer.co.uk has found that some games are vastly different in price. BlackBerry owners will have to pay Glu Mobile £7.85 for a game that costs £1.79 on the iPhone App Store for example.

But I don't live in the UK


Currently the App World store is only available in the UK, Canada and the US. Europe and the rest of the world have been promised. RIM is keeping quiet on the launch dates, but says it should be soon. At least they have confirmed it.