Hello Rob,
you just need to enable channel-groups on the trunk interfaces. use either pagp or lacp on the interfaces, with appropriate modes (active/passive/auto or desirable).. Are you doing etherchannel with Foundry switch ? if so, please check the configs on foundry.
With respect to cisco, u can use the following URL for configuring etherchannels:
http://cisco.com/en/US/products/hw/switches/ps4324/products_configuration_guide_chapter09186a008011c8a9.html
Hope this helps.. let us know if you need anything else in this..
Raj