I use Dino Chiesa's powershell-mode (see http://blogs.msdn.com/dotnetinterop/archive/2008/04/10/run-powershell-as-a-shell-within-emacs.aspx) to run powershell as a shell within Emacs on Vista and it's another good reason not to leave Emacs.
But (being German) I need to use non-ascii characters like äöü in strings in my powershell work. These somehow get scrambled and end up not correctly in the powershell code. I played around with some settings of the coding systems but have not been successful. Any hints? Thanks in advance! Martin