Setting up the brand new PowerShell v.2 remotely in a domain environment is easy: simply run
Set-WSManQuickConfig
As long as you have proper privileges to run this command, it does everything automatically: it runs the WinRM service, sets up a PowerShell listener and a firewall exception. To play with remotely, run this on every computer you want to connect to as it is required on both ends. Then, run any command remotely like this:
Invoke-Command { Stop-Process Spooler -force -whatif } `
-computername test123
-computername test123
You should note that remote by default requires Kerberos authentication, so it will only work in a domain environment. You learn how to configure WSMan appropriately to make it work in simple peer-to-peer environments, in another tip.