This is easy to do with javascript if that is the solution you want,, see below..
<form name="Form1">
<input name="Input1" value="type text here "
onchange="this.value=this.value.toUpperCase();"><br>
<input name="Input2" value="and it will be "
onchange="this.value=this.value.toUpperCase();"><br>
<input name="Input3" value="made upper case"
onchange="this.value=this.value.toUpperCase();"><br>
</form>
(The more ASP.NET I do, the more Javascript I find myself using)