The following will show all VM's in the connected vCenter environment that have snapshots and will output the information showing the VM name, snapshot name and snapshot creation date.
Get-VM | Get-Snapshot | Select VM, Name, Created
The following will remove all snapshots with an associated VM.
Get-VM "ServerName" | Get-Snapshot | Remove-Snapshot -confirm:$false -RunAsync
This is just for my own personal reference really when I want to quickly check the environment I'm working in.
A fully featured and robost script can be run in the environment using virtu-al.net's vCheck script. I recommend checking it out as it is pretty amazing;