list applied Irules for a specified VIP

While all this could be done in fewer lines just as easily, here's some code that should help using iControlRest.

$f5Host = "f5.example.com";
$f5Cred = (Get-Credential);
$prefix = "https://$f5Host/mgmt/tm";
$vip    = "/MY_VIP_NAME";                        You can leave this variable blank to return all the VIPs and their iRules
$resp   = Invoke-RestMethod -Method GET -Uri "$prefix/ltm/virtual$($vip)?`$select=fullPath,rules" -Credential $f5Cred;
$list   = ($resp.items, $resp, 1 -ne $null)[0];  REF: http://stackoverflow.com/questions/10623907/null-coalescing-in-powershell
$list;

In that case, you could use Putty's

Plink.exe

tmsh

$f5Host     = "f5.example.com";
$f5Cred     = (Get-Credential);
$plinkPath  = 'c:\PATH\TO\plink.exe';
$vip        = "MY_VIP_NAME";  Or blank for all VIPs
$tCmd       = "tmsh list ltm virtual $vip rules";
$command    = "& `"$plinkPath`" -l ""{0}"" -pw ""{1}"" {2} ""{3}""" -f @($f5Cred.Username, $f5Cred.GetNetworkCredential().Password, $f5Host, $tCmd);
$response   = Invoke-Expression $command;
$response;

You'll will have to parse the response to get the data in a more usable format, however.

You could also use the older SOAP based iControl, but I don't have an example for that one.