Try:
Code:
<iframe src="http://google.com/search?q=<%=Request.form("q") %>">
While Request and Request.form are similar, they are not the same.
Here's some test code that does work so that you can have another example.
Code:
<body>
<form method="post" action="test.asp">
<input type="text" name="q" size="30" /><br />
<input type="submit" name="B1" value="Search Google!" /><br />
</form>
<iframe src="http://www.google.com/search?q=<%= request.form("q") %>" frameborder="0" width="98%" height="400"></iframe>
</body>