You can add Sharepoint 2010 PowerShell admin rights to an account using this powershell cmdlet:

Add-SPShellAdmin [-UserName] <String> [-AssignmentCollection <SPAssignmentCollection>] [-Confirm [<SwitchParameter>]] [-database <SPDatabasePipeBind>] [-WhatIf [<SwitchParameter>]]

Add-SPShellAdmin -UserName CONTOSOUser1

Add-SPShellAdmin -UserName CONTOSOUser1 -database 4251d855-3c15-4501-8dd1-98f960359fa6