Add url examples to the book.

[michaellwest]

$site = [Sitecore.Sites.SiteContextFactory]::GetSiteContext("usa")
$url = New-UsingBlock (New-Object Sitecore.Sites.SiteContextSwitcher $site) {
    $pageItem = Get-Item -Path "master:" -Id "{50BE527C-7241-4613-A7A9-20D0217B264B}"
    [Sitecore.Links.LinkManager]::GetItemUrl($pageItem)
}

$url = New-UsingBlock (New-Object Sitecore.Sites.SiteContextSwitcher $site) {
    $mediaItem = Get-Item -Path "master:" -Id "{CBE06C33-59DE-4B34-968D-19EBA886BC84}"
    [Sitecore.Resources.Media.MediaManager]::GetMediaUrl($mediaItem)
}

[michaellwest]

Updated with page url.