We don't have any iSCSI hosts so I can't test this, but I can get all kinds of fibre channel info starting with this command:
Get-VMHost | Get-VMHostHba
I found this page online that may help you with more detailed iSCSI info. It's a bit dated but should help.
Edit: here's a better starting point.
Get-Cluster -name Clustername | Get-VMHost | Get-VMHostHba -type iscsi | Format-List
Get-VMhost | Get-VMHostHba -Type IScsi | Select @{n="Cluster";e={$_.VMHost.parent.name}}, VMHost, IScsiName