If you're using iSCSI, look into binding the vmkernel ports to uplinks (does not require a port channel):
If you're using NFS, a port channel really has no affect unless very specific conditions are met. I've written a 4 part series on it here:
http://wahlnetwork.com/category/deep-dives/nfs-on-vsphere/
The specific post that goes over single subnet NFS is here:
http://wahlnetwork.com/2012/04/23/nfs-on-vsphere-technical-deep-dive-on-same-subnet-storage-traffic/