>Im using IE.. does not work for me..

It works for me! What version of IE are you using?

>Plus where do you put that code?
>is there a mouseover event?
You can put the code in the event, method or function in Codebehind of the ASPX page where you retrieve the data from the database. Below is a sample of such code in then Page_Load event:

private void Page_Load(object sender, System.EventArgs e)
{
*let's say that you've retrieved your data into a DataSet
*mybutton is a server side button on the page
 foreach(DataRow loRow in this.myDataSet.Tables["mytable"].Rows)
 {
  this.mybutton.Tooltip += loRow["myfield"].ToString().Trim() + ((char)13).ToString();
 }
}

You don't need to implement a MouseOver Event if you set the Tooltip property of the button.
When the ASPX page is processed and sent back the client(browser), the Tooltip becomes the Title of the HTML control e.g.:

<input type="submit" name="mybutton" value="send" Title="The tips">