I am going through some of my older sites where I have a contact form and in IE8 there always is a vertical scroll bar displayed for my textareas, even when there is no content.
Use overflow: hidden and all will be well.
<HTML> <BODY> <textarea rows="10" style="overflow: hidden;"/> </BODY> </HTML>
I can't test on IE8 right now, but I can tell you that this works in IE6:
textarea { overflow-y: auto; }