Inspired by the Posh-Git project (http://github.com/dahlbyk/posh-git)

Posh-hg provides a custom prompt and tab expansion when using Mercurial from within a Windows Powershell command line.

For more details, see this post on Jeremy's blog:
http://www.jeremyskinner.co.uk/2010/04/21/using-mercurial-with-windows-powershell/

To install posh-hg, download the latest source from GitHub or CodePlex:
http://github.com/JeremySkinner/posh-hg/zipball/master
http://PoshHg.codeplex.com

...and add the following code to your Powershell profile (usually C:\Users\Username\Documents\WindowsPowershell\Profile.ps1)

. path\to\posh-hg\profile.example.ps1

Alternatiely, you can copy the contents of the profile.example.ps1 file in to your profile.ps1