Can someone please explain the difference between an Etherchannel port and a trunk port or refer me do a doc where I can read up on it?
The beauty of etherchannel is that it is considered one link. So say you two switches and you want redundant links, so you connect two cables between the switches. STP will not allow traffic over one of the links so you are only going to use one link at a time.
Now if you configure an etherchannel group between the two switches with two connections, STP thinks of the etherchannel group as one link and so both links will transmit/receive traffic in a more or less load balanced fashion. If one of the links in the etherchannel group fails, STP does nothing because it still looks at the etherchannel group as one link. You will just have 1/2 the bandwidth on the etherchannel group.
It is often good to use etherchannel group connections between switches because:
1. You get more bandwidth between switches.
2. You get redundancy in case one of the connections fails, the etherchannel group will continue to use the connections that remain.
3. You don't have to wory about STP.