Limiting Internet Access

[tepare at lilac.nhsl.lib.nh.us]

Can anyone recommend some specific software packages a public library can
use to limit Internet access to a few specific sites.  The library provides
unlimited Internet access on several computers.  Due to the number of
surfers, they also want to have a computer dedicated to certain services
the library subscribes to such as FirstSearch and SearchBank.  They've
tried self policing (signs requesting people to refrain from surfing)
without success.

TIA,
Theresa Pare'
NH State Library
tepare at lilac.nhsl.lib.nh.us