Question: I have seen similar posts but couldn't find any answer..

Kindly advise whether its possible or not?

Answer: 
Are you talking about 3rd party applications or the inbuilt applications of the iPhone?

If you are talking about 3rd party application then forget it.. As told by @KingOfBliss apple restricts it.

And if you want to open inbuilt applications like camera, photo, contacts,safari web then you can do it.

You can get sample code for implementing all these from [here](http://developer.apple.com/library/ios/navigation/#section=Resource%20Types&topic=Sample%20Code)...

Hope it helps...

hAPPY iCODING...
Apple restrict you to open 3rd party application, but you can open some application like safari,contacts,etc.,