They can offer either a cable modem based service or a 2MB HDSL (leased line) service. The first is sold under the Business Essentials brand and costs about £79/mo for 1 MB. The HDSL comes in at about £7-8k per year.
We have the cable service at work and the link has proved reliable and fast. Luckily though we don't rely on NTLs email or news servers. The Business Essentials servers are shared with the NTL:home service so have suffered all the faults reported in here.
I am not sure if you get better maintained service for email etc if you go for the leased line package.
Phone 0800 052 0800 and follow the Business sales path. You will eventually find someone who will sell you either of the above offerings, beware though they are sold by completely different departments.
There is a site:
http://businessessentials.ntl.com/
But this rarely changes, the status page never updates and it gives little info. It does provide a door into servicing your own account though.
APS