To test whether or not your server is up, you can use a browser, or even simpler, telnet to port 80 (or other, as above) of your machine:
$ telnet localhost 80
Trying 127.0.0.1...
Escape character is '^]'.
GET / HTTP 1.0
HTTP/1.0 200 OK
Date: Sun, 16 Jul 2000 19:09:37 GMT
Server: Apache/1.1.3
Content-type: text/html
Note that YOU actually have to type the line "GET / HTTP 1.0" followed by two carriage returns.
What you'll get in return is the response header "HTTP/1.0 200 OK" which includes the response code "200" - meaning that your server responded as it should. You'll also notice the line "Server: Apache/1.1.3" or similar, depending on your version of Apache. This serves to identify the software you're using to serve your material.
All servers do this, and is how Netcraft performs their Web server software survey.
Haven't tried it myself. (And it was surprisingly difficult to find!)
HTH.
Cheers,
Scott.