Facebook,twitter and email not share using share kit

I am a new ios developer and i have created an ios app where i want to share link in to the Facebook,twitter and mail.I am using Xcode 4.2 and ios 5. I browse lot of side and used lot of sample code. But i am not able to do this.Using sharekit library i am able to share image but not able to share link.

Can any one share me any link or any example source code by which i am able to do this. Thanks in advance and sorry for my bad English.

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