With the help of Kuma:

http://groups.google.com/group/microsoft.public.windows.powershell
/browse_thread/thread/9b10ea1270dfd0ad/eb78a0bc226837d6#eb78a0bc226837d6

I have picked up this gem, which gives all the physical IPs on a system:

0..1 | %{([System.Net.DNS]::GetHostEntry(""))
.AddressList[$_].IPAddressToString}

/\/\o\/\/ came up with the following brilliance:
http://thepowershellguy.com/blogs/posh/archive/2008/06/30/powershell-get-ipconfig-function.aspx?
CommentPosted=true#commentmessage

[System.Net.NetworkInformation.NetworkInterface]::GetAllNetworkInterfaces()
|% {$_.getIPProperties().UnicastAddresses[0]}


Address : 192.168.0.5
IPv4Mask : 255.255.255.0
IsTransient : False
IsDnsEligible : True
PrefixOrigin : Dhcp
SuffixOrigin : OriginDhcp
DuplicateAddressDetectionState : Preferred
AddressValidLifetime : 349435
AddressPreferredLifetime : 349435
DhcpLeaseLifetime : 349435

Address : 127.0.0.1
IPv4Mask :
IsTransient : False
IsDnsEligible : True
PrefixOrigin : Manual
SuffixOrigin : Manual
DuplicateAddressDetectionState : Preferred
AddressValidLifetime : 3079514780
AddressPreferredLifetime : 3079514780
DhcpLeaseLifetime : 3079514780




[System.Net.NetworkInformation.NetworkInterface]::GetAllNetworkInterfaces()
|% {$_.getIPProperties}


MemberType : Method
OverloadDefinitions : {System.Net.NetworkInformation.IPInterfaceProperties GetIPProperties()}
TypeNameOfValue : System.Management.Automation.PSMethod
Value : System.Net.NetworkInformation.IPInterfaceProperties GetIPProperties()
Name : GetIPProperties
IsInstance : True

MemberType : Method
OverloadDefinitions : {System.Net.NetworkInformation.IPInterfaceProperties GetIPProperties()}
TypeNameOfValue : System.Management.Automation.PSMethod
Value : System.Net.NetworkInformation.IPInterfaceProperties GetIPProperties()
Name : GetIPProperties
IsInstance : True

MemberType : Method
OverloadDefinitions : {System.Net.NetworkInformation.IPInterfaceProperties GetIPProperties()}
TypeNameOfValue : System.Management.Automation.PSMethod
Value : System.Net.NetworkInformation.IPInterfaceProperties GetIPProperties()
Name : GetIPProperties
IsInstance : True

I find it simply amazing that Powershell can use the .NET to find the Broadcast and Loopback with little complication, but not the host IP Address:
[System.Net.IPAddress]::Broadcast.IPAddressToString
or
[System.Net.IPAddress]::Loopback.IPAddressToString

I can find all NetworkInterface information BUT the IP easily enough:
[System.Net.NetworkInformation.NetworkInterface]::
GetAllNetworkInterfaces()

But if I want my local host IP address through .NET I need some kludge like:
$host_name = [System.Net.Dns]::GetHostName() ; [System.Net.Dns]::Resolve("$host_name")

Or I can dredge up some other not quite satisfactory kludge from gwmi:

$NetworkInfo =gwmi -query "SELECT * FROM Win32_NetworkAdapterConfiguration"
function NetworkInfoSort {$NetworkInfo | Select-Object IPAddress,Description,Index,DefaultIPGateway | sort-object Index}
NetworkInfoSort

gwmi -class win32_NetworkAdapterConfiguration | %{ $_.IPAddress }

gwmi -query "SELECT IPAddress FROM Win32_NetworkAdapterConfiguration" | Select IPAddress

I wish I could just do something like:

[System.Net.IPAddress]::LocalHost.IPAddressToString
or
[System.Net.NetworkInformation.NetworkInterface]::
GetAllNetworkInterfaces.IPAddress
or
Get-ipconfig

Still relatively confused on how to use the .NET through Powershell. Here are some simple examples that were easy to find because they have accessible overloaded interfaces (??):

$Ping = new-object System.Net.NetworkInformation.ping
$Ping.Send("192.168.0.1")
Status : Success
Address : 192.168.0.1
RoundtripTime : 1 ms
BufferSize : 32
Options : TTL=127, DontFragment=False


[System.Net.Dns]::Resolve("google.com") | fl *
HostName : google.com
Aliases : {}
AddressList : {64.233.167.99, 72.14.207.99, 64.233.187.99}


[System.Net.Dns]::GetHostName()
rmfmedia

[System.Net.NetworkInformation.NetworkInterface]::GetAllNetworkInterfaces()

Id : {0348D5D7-6D83-44C8-B556-B29466698340}
Name : Wireless Network Connection
Description : Intel(R) PRO/Wireless 3945ABG Network Connection - Packet Scheduler Miniport
NetworkInterfaceType : Ethernet
OperationalStatus : Up
Speed : 54000000
IsReceiveOnly : False
SupportsMulticast : True
....

[System.Net.NetworkInformation.NetworkInterface]::GetIsNetworkAvailable()
True