Is there a network switch with a web interface that reports bandwidth use per port?

Solution 1:

The marketing term for these switches are "Smart Switches" for one that at least have web management (access) capabilities. These switches typically do not have a CLI, but they have most of the aspects of a "managed" switch.

They are targeted at the SMB market where most of the manufacturers offer something similar to fit the lower-middle of their product lines, just underneath the full "managed" switches (which do offer the capability you are seeking and Ben Pillow identified) or along side them.

Solution 2:

I don't know of any switch that shows bandwidth on the web interface. However, the higher end switches like HP Procurve, Dell PowerConnect and Cisco do have SNMP that will provide that information. Solarwinds has a free tool where you can monitor the device via SNMP (free version is limited to one device). There is also MRTG which will provide bandwidth graphs and more. Bottom line is you would need a switch that supports SNMP.