http://technet.microsoft.com/en-us/library/ff678226.aspx
Examples
Adding users and claims to a site from PowerShell
http://blogs.msdn.com/b/brporter/archive/2010/12/02/adding-users-and-claims-to-a-site-from-powershell.aspx
Changing the Item-Level Permissions Settings for a Document Library requires PowerShell http://www.hersheytech.com/Blog/SharePoint/tabid/197/entryid/28/Default.aspx
PowerShell script to capture and report on all SharePoint permissions through a site collection http://localgovernmentsharepoint.wordpress.com/2012/01/25/powershell-script-to-capture-and-report-on-all-sharepoint-permissions-through-a-site-collection/
The PowerShell script I (Todd) use to create Active Directory users http://www.toddklindt.com/blog/Lists/Posts/Post.aspx?ID=362
