PowerShell v2 has 2 default locations for modules – in the install directory and in your profile. My demo laptop is set to dual boot Windows 7 & Windows 2008 R2. It would make sense to only maintain one set of files for the modules I write. There is a PowerShell automatic variable that sets where PowerShell looks for modules. To add my own folder to that path I just add
$env:PSModulePath = "C:\Scripts\Modules;" + $env:PSModulePath
to my profile. The modules will be available now from either machine. Need to change drive letter in the Win 2008 profile but otherwise just the same.