One way to test if TRACE has been disabled is to telnet to port 80 (type the stuff in red):
telnet myserver.com 80
Connected to myserver.com (188.8.131.52).
Escape character is '^]'.
TRACE / HTTP/1.1
<press enter a few times>
If a 400 error is printed then you are secured:
HTTP/1.1 403 Forbidden
Date: Tue, 11 Nov 2008 15:26:33 GMT
Server: Apache/2.0.52 (OS Version)
Here is an example of how to use telnet to test HTTP for future reference: