The apps are carefully checked by apple before they are released, anything dangerous would have detected. You could contact apple if you have concerns about a specific app.
In some app answer is Yes.
apple create the apps on iPhone
As long as your computer has itunes that is authorised on the same itunes account as your iphone, then it will automatically transfer all your iphone apps onto the computer
There a many good iPhone blog apps. The most common blog app would be snap guide.
no, iphone apps are only made to work with iphones, not other phones...
There is no way to do that. If you jailbreak your iPhone there is an app on Cydia that does that.
sometimes but they can give you a virus
The android phone has some of the same apps, but not all, vice versa.
You buy the iPhone app
apple create the apps on iPhone
no you cannot use ipod and iphone apps on itunes, but you can buy the apps on itunes and put them on your ipod and iphone
Although iPads can download apps made only for iPhone/iPod Touch, the iPhone can only download iPhone or iPhone/iPad apps. Apps made only for the iPad do not appear on the App Store. Luckily most of these apps have an iPhone counterpart such as Angry Birds (iPhone) and Angry Birds HD (iPad only).
Microsoft voices do not give your computer a virus but make sure not to open other apps that may crash your computer.
The good news is that IPhone tracking is available and the ... you can look out for such as the GPS tracking ... iPhone Jailbreak News - iPhone Apps - iPhone ...
yes, but not all iphone 4 apps are available on the iphone 3gs/3g/2g becuase they are too high resolution apps, or need a front facing camera.
As long as your computer has itunes that is authorised on the same itunes account as your iphone, then it will automatically transfer all your iphone apps onto the computer
No you can not share iPhone apps.
By the time I answer this question there are ~285,000 iPhone / iPod Touch apps on the iTunes App Store.