Here is some neat code to open IE using tabs
$ie = New-Object -ComObject InternetExplorer.Application
$ie.Navigate2("www.microsoft.com")
$ie.Navigate2("technet.microsoft.com",0x1000)
$ie.Navigate2("sharepoint.microsoft.com",0x1000)
$ie.Navigate2("office.microsoft.com",0x1000)
$ie.Navigate2("randelhall.blogspot.com",0x1000)
$ie.Visible = $true