Media for freeware sniffer for windows?

I've use the SPAN command on one of the ports on my main backbone switch so that I can attached a sniffer to it.

I"ve tried Ethereal but unfortunately I can't find a way to separate the port #'s when loading the exported capture in Excel.

I'm just looking for something simple that can export the following data in separate columns:

SOURCE IP SOURCE PORT DESTINATION IP DESTIONATION PORT PROTOCOLS (UDP, TCP, etc)

It also has to have the option to start writing the capture to new log files when the log file has reach a certain size.

That's it...