We have a 250 user network running on Win2k and recently installed
SonciWall Pro300 security appliances to, i.e., monitor internet usage.
Most webusage stats include only an IP address, such as 64.215.164.101
What are the best ways to resolve these addresses so that we can tell
what sites users are visiting?

There are several ways to find out whatīs behind IP addresses. 

1.
On a W2k system I use a nice program called 
dbzNetBuddy 
which may do all you need.
Itīs avaiable at:
( http://www.division-by-zero.de/dbz/index.asp?main=/dbz/tools/netbuddy_main_eng.htm&headergif=tools
)

The queries you can do with this program include a "whois" search
which will lead you to the server address of a given IP. Often you
will be lead to the address of a webhosting company as many webpages
are not hosted on own servers but on webspace of an internet service
provider.
The program has some more options you might find usefull.

2.
If you prefer an online solution (which is nice if you do not want ro
install any software on you pc) please visit
Zoneedit at:
( http://www.zoneedit.com/lookup.html )
All you got to do there is enter the IP you want to look up in the box
"Reverse Lookup" and you will get the server information
examples:
IP 66.135.192.88 will reveal to be the pages of ebay.com
IP 66.218.71.198 will lead to the yahoo.com pages
IP 217.13.201.20 will lead to the internet service provider where my
webpage is hosted.

I hope this helps to solve you problem. 

till-ga

Search strategy: none, I knew those solutions as I use them every day.