Try this:

String= "Change your preferences at <a 
href=\"http://p2p.wrox.com/manager.asp\">http://p2p.wrox.com/manager.asp<a> 
receive mail for every message, receive a digest or no mail."

You have to specify that the text is a link to another URL.  This done by 
using the anchor tag '<a>' along with the attribute 'href'.

:
>hi all,
>   Iam facing little bit problem in the string
>handling.
>My question is, let suppose,
>String= "Change your preferences at
>http://p2p.wrox.com/manager.asp . Select to
>receive mail for every message, receive a digest or no
>mail."
>
>I want to present this string on the browser, iam not
>getting hyperlink on the corresponding url of
>http://p2p.wrox.com/manager.asp.
>In the sense, iam getting text on the browser without
>any hyperlink on the specified url of
>http://p2p.wrox.com/manager.asp.
>
>Please advice me or if possible provide me a piece of
>code to accomplish this task.
>  Thanks in advance.