How can I connect my iPhone 4s to other handset via Bluetooth ?
You can't by itself. There are a few apps in the app store that will enable you to possibly do this depending upon the phone you are transferring to.
Most of the apps that will allow some BT connectivity to other phones are iOS to iOS only. Take a look at Bump. It's cross platform.
Would you like to tell me the name of such type of apps?
No, because I don't use any of them. Anything that I want on my phone, I sync with iTunes.
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