Etherchannel Cisco 3750 Stacked Switches

When adding portchannels to a switch configuration that span more than one stacked switch, it is advisable to upgrade to the latest IOS version.  The most current is:  12.2(25)SEE3

This feature is a very robust way of aggregating links between switch ports on the same subnet.  This configuration not only allows for port redundancy, but switch redundancy, as well.

Networking switch Cisco