From some example scripts, I'd say that Perl is one of several direct and indirect influences. For comparison, look at how they use Perl in their examples here here.

There's even an example of a grep-like tool that looks like Get-Shapes | Where-Object {$_.Color –eq "Orange"}, complete with '$_'. That's found in the PowerShell Manual and the Where-Object doc is at the 'cmdlets' docs.

There's also some PHP touches to the syntax that I see. It's also inspired by actual shells, as you can dot-source other files.

It appears that anything written in PowerShell is going to emit objects, but that it's smart enough to handle text instead when confronted with scripts in other languages.

The interview with the chief architect of the package, Jeffrey Snover, says he likes several languages, including Perl, but that they all have shortcomings he's trying to alleviate in PowerShell and the related utilities.

JS: Like most people, I have a love/hate relationship with the existing tools. I love the interactivity and composability of KSH/utilities but I hate their inconsistency and the need to do text parsing. I love the power and programmability of PERL and TCL but I hate their idiosyncrasies and their lack of a good interactive experience. I love the consistency and production-orientation of VMS DCL and AS400’s CL but I hate their composability model. I love the UNIX model of surfacing everything through the filesystem but I hate the anemic semantics of the filesystem.

I have to say, the language itself doesn't look bad. PowerShell, the terminal, and some other tools are aimed primarily at Windows admins, though, and not at general-purpose programming tasks. The docs, examples, and interview responses all seem to point to WSH, VB for Applications -- er, I mean VBScript, and such as the comparable technologies. I'd expect about the same support for developers as with those toola -- that is, not much compared to Visual C++ and Visual Basic .NET environments, documentation, and updates.