Multiple hostnames on single ip-address

[Steffen Tang]

I am very new to DNS and Bind in perticular so please bare with me if my
question sounds a bit weird.

My problem is that we currently are hosting about 20 websites for some
customers, which is possible bescause we have 255 ip-addresses. The
solution has been a IIS on NT4, with each site having its own ip-address
which is defined in our DNS.
The problem is that we are changing ISP, and now only have 16
ip-addresses, so my question is therefore if it is possible to avoid
using a ip-address for each site. I have heard something about virtual
hosting on the Apache server, and the problem is therefore how we should
configure our DNS (we are planning to use BIND).

Don't hesitate to contact me if you would like me to elaborate.
-- 
Med venlig hilsen/Best regards

Steffen Tang
Netventure