Question : Problem: Determining T1 utilization accross cisco 1721

I need an easy way to look at the aveage utilization of a T1 circuit running through a cisco 1721.

I am basically looking for some indications of how much spare bandwidth I have over a given period of time....

Any suggestions are greatly appreicated.  Keep in mind I don't work on Cisco's very often.

Answer : Problem: Determining T1 utilization accross cisco 1721

MRTG is great. Windows port here
http://www.openxtra.co.uk/products/freestuff.php

Other options include something like SolarWinds Orion. Free 30 day eval, but it's an awesome product if you have several routers/switches/servers that you need to monitor:
http://www.solarwinds.net

PRTG is another one, free for "home" use - ie. one single interface on one single router.
http://www.paessler.com/prtg