Newbie on JtextArea swing component

Hi,

Probably a very basic question but I can't find any useful pointers.
If someone can point me in the right direction please...?

I am using Netbeans 5.5 and have a JTextarea inside a JScrollPane. I
am reading a file and adding the lines one at a time to the JTextare
with the following code:

            try
            {
                FileInputStream fstream = new
FileInputStream(SrcFile);
                DataInputStream in = new
DataInputStream(fstream);

                // Continue to read lines while
                // there are still some left to read
                jT_SourceCode.setText(in.readLine()+"\n");
                while (in.available() !=0)
                {
                    jT_SourceCode.append(in.readLine()+"\n");
    }
    in.close();
            }

and this works very nicely. I can see the contents of my file in the
textarea object. I want to be able to set an arbitrary line as the top
visible line in the GUI and have the line highlighted.

Can somebody point me at a tutorial or example for this please?

TIA,

Richard.