I assume you have a Linux machine around. If you don't install one. :)
This will time how much time does it take to pull 1000 pages from the server:
time for i in `seq 1000`; do wget http://127.0.0.1/~elcuco/test.php; done
Now, how about concurrent loads? There is a utility called "apache benchmark", lets have a test:
ab -c 20 -n 100 http://127.0.0.1/~elcuco/test.php
This pulls 100 pages, while keeping 20 concurrent downloads. Here is a real life demo, it's self explaining.
[elcuco@pinky ~]$ /usr/sbin/ab -c 20 -n 100 http://serverfault.com/questions/22785/stress-testing-a-hosted-iis-server
This is ApacheBench, Version 2.0.40-dev <$Revision: 1.146 $> apache-2.0
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Copyright 2006 The Apache Software Foundation, http://www.apache.org/
Benchmarking serverfault.com (be patient).....done
Server Software: Microsoft-IIS/7.0
Server Hostname: serverfault.com
Server Port: 80
Document Path: /questions/22785/stress-testing-a-hosted-iis-server
Document Length: 30691 bytes
Concurrency Level: 20
Time taken for tests: 19.642924 seconds
Complete requests: 100
Failed requests: 0
Write errors: 0
Total transferred: 3151576 bytes
HTML transferred: 3129271 bytes
Requests per second: 5.09 [#/sec] (mean)
Time per request: 3928.585 [ms] (mean)
Time per request: 196.429 [ms] (mean, across all concurrent requests)
Transfer rate: 156.65 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 266 480 506.2 397 3328
Processing: 1227 3236 1559.4 2963 9943
Waiting: 287 495 277.6 443 1836
Total: 1499 3716 1613.2 3433 10285
Percentage of the requests served within a certain time (ms)
50% 3433
66% 4040
75% 4321
80% 4953
90% 6056
95% 6795
98% 9139
99% 10285
100% 10285 (longest request)