How to create a sub site using Power Shell scripts in SharePoint 2010?
To add a new subsite use the New-SPWeb cmdlet
New-SPWeb –url <new site url> -name <new site name> -template <template name>
Additional cmdlet which can be used:
AddToTopNav, UniquePermissions, UseParentTopNav
Sample Script to create new sub site in SharePoint using PowerShell
New-SPWeb –url http://vsharepoint/HyperV -name "All about HyperV"
-template STS#0 –AddToTopNav –UniquePermissions –UseParentTopNav
Template Names: http://virtualizesharepoint.com/2012/01/03/site-template-names-and-ids-in-sharepoint-2010/