Accessing Frames with internet Explorer

Hi,

I am using PowerShell to navigate to a website using the following code:
$ie = new-object -comobject internetexplorer.application
$ie.visible = $true
$ie.navigate(http://www.website.com)
while($ie.busy){Start-Sleep 1}

The website contains several nested framesets. I am unable to access the frames in the document. 

Any ideas how to walk through the individual framesets and frames?