XLOCK Hint is ignored even though specifying explictly?

Interesting newbie question on the forums to share. I am selecting a value from a table(column).I do not want any 2 users can select same value at the same time..in other word 1 value only be selected by individual user. in order to do it I am simply using with (xlock) in select statement within begin tran...commit tran. In this way I am hoping to avoid above mentioned situation. But it is not working...as when I fire second select statement (without commit tran of first statement) for same rows...(<a href="http://sqlserver-qa.net/blogs/tools/archive/2007/09/11/xlock-hint-is-ignored-even-though-specifying-explictly.aspx">read more</a>)<img src="http://sqlserver-qa.net/aggbug.aspx?PostID=1981" width="1" height="1">