This only finds sites which have applications; we won't even see any sites which don't have apps.

Import-Module WebAdministration
$result = @()
dir IIS:\Sites | ForEach-Object {$result = Get-WebApplication -Site $_.Name}
$result | ogv

This lists all sites along with any applications they might have. But it also lists the same site repeatedly if a site has more than one app.

Import-Module WebAdministration
$result = @()
$sites = dir IIS:\Sites
foreach ($site in $sites) {
    $applications = Get-WebApplication -Site $site.Name
    if ($applications) {
        foreach ($app in $applications) {
           $result += New-Object PSObject -property @{
           SiteName = $site.Name
           SiteID = $site.ID
           PhysicalPathSite = $site.PhysicalPath
           AppName = $app.Path
           AppPool = $app.ApplicationPool
           PhysicalPathApp = $app.PhysicalPath}
        }
    }
    else {
        $result += New-Object PSObject -property @{
        SiteName = $site.Name
        SiteID = $site.ID
        PhysicalPathSite = $site.PhysicalPath
        AppName = $null
        AppPool = $null
        PhysicalPathApp = $null}
    }
}
$result = $result | select SiteName, SiteID, PhysicalPathSite, AppName, AppPool, PhysicalPathApp
$result | ogv

This suppresses repeating the site attributes when a site has several apps. Maybe not best choice if you need to sort results, but looks better if you don't have to sort. Or if you do want to sort on either sites or apps, better sort them before display/export.

Import-Module WebAdministration
$result = @()
$sites = dir IIS:\Sites
foreach ($site in $sites) {
    $applications = Get-WebApplication -Site $site.Name
    if ($applications) {
        $i=0
        foreach ($app in $applications) {
           $i++
           if ($i -le 1) { # show site info first time around ...
                $SiteName = $site.Name
                $SiteID = $site.ID
                $PhysicalPathSite = $site.PhysicalPath
            }
           else { # ... but don't keep showing the same site info for every app of that site
                $SiteName = $null
                $SiteID = $null
                $PhysicalPathSite = $null
            }
           $result += New-Object PSObject -property @{
           SiteName = $SiteName
           SiteID = $SiteID
           PhysicalPathSite = $PhysicalPathSite
           AppName = $app.Path
           AppPool = $app.ApplicationPool
           PhysicalPathApp = $app.PhysicalPath}
        }
    }
    else {
        $result += New-Object PSObject -property @{
        SiteName = $site.Name
        SiteID = $site.ID
        PhysicalPathSite = $site.PhysicalPath
        AppName = $null
        AppPool = $null
        PhysicalPathApp = $null}
    }
}
$result = $result | select SiteName, SiteID, PhysicalPathSite, AppName, AppPool, PhysicalPathApp
$result | ogv

This works OK if you happen to already be on the web server in question

Import-Module WebAdministration
$sites = Get-ChildItem IIS:\sites
$bindings = $sites | foreach-object {$_.Bindings} | foreach-object {$_.Collection} | foreach-object {$_.BindingInformation}
$bindings | Sort-Object

But if you're not already on the web server in question, starting a remote session can speed things up. I also like to split out the various parts of the returned object into separate columns.

$serverName = "someWebServer"
$Session = New-PSSession -ComputerName $serverName
$block = {Import-Module WebAdministration
    $sites = Get-ChildItem -path IIS:\Sites
    $bindings = $sites | foreach-object {$_.Bindings} | foreach-object {$_.Collection} | foreach-object {$_.BindingInformation}
    $bindings | Select @{name="IP"; expression={$_.Split(":")[0]}}, @{name="port"; expression={$_.Split(":")[1]}}, @{name="domain" ; expression={$_.Split(":")[2]}} | sort domain | ft
}
Invoke-Command -Session $Session -ScriptBlock $block

In this case, I was most interested in sorting by domain. But Often I want to know if an IP address is being used, so I'll sort by that instead. Unfortunately, you can't pipe to an Out-GridView in a remote session and I haven't figured out yet how to return a variable's result to the local session so I can pipe that to an Out-GridView. So, I content myself with Format-Table.

This alternate command which throws in a Group-Object (assuming you use the same $Session variable you created above). But if you want IP addresses, well, it doesn't include those.

$block = {Import-Module WebAdministration
    Get-WebBinding | % {
        $name = $_.ItemXPath -replace '(?:.*?)name=''([^'']*)(?:.*)', '$1'
        New-Object psobject -Property @{
            Name = $name
            Binding = $_.bindinginformation.Split(":")[-1]
        }
    } | Group-Object -Property Name | sort Name |
    Format-Table Name, @{n="Bindings";e={$_.Group.Binding -join "`n"}} -Wrap
}
Invoke-Command -Session $Session -ScriptBlock $block

display names of website along with each site's binding (same as above without $block)

Get-WebBinding | % {
    $name = $_.ItemXPath -replace '(?:.*?)name=''([^'']*)(?:.*)', '$1'
    New-Object psobject -Property @{
        Name = $name
        Binding = $_.bindinginformation.Split(":")[-1]
    }
} | Group-Object -Property Name |
Format-Table \Name, @{n="Bindings";e={$_.Group.Binding -join "`n"}} -Wrap