I had a lot of trouble getting Omega Sass to compile properly without gem dependency errors. Below is a quick guide to getting your Windows Development Environment up and running quickly for the Omega 4 Theme using Pik (an RVM alternative), and Bundler.

1. Download and install Ruby 1.9.3 and DevKit from 
   

   http://rubyinstaller.org/downloads/

Unlike on UNIX based systems, installing and configuring RVM on a Windows machine properly in order to be able to use the new possibilities in Drupal's Omega 4 theme could become a difficult task. But running that process through the cygwin environment makes it possible.

Installing cygwin and required dependencies

Make sure you install the 32-bit version of cygwin, as otherwise you could get errors when trying to compile your ruby when installing it through rvm. So Install cygwin with following packages and their dependencies:

Uniform Server Drupal 7 Setup (Verbose)

An explicit guide to setting up an easy Drupal development environment utilizing the Uniform Server. “The Uniform Server is a WAMP package that allows you to run a server on any MS Windows OS based computer. It is small and mobile to download or move around and can also be used or setup as a production/live server.” http://www.uniformserver.com/

Mike Anello's (ultimike) video tutorial: http://www.youtube.com/watch?v=3SPyQ3KJLJg

In case of difficulty:
http://wiki.uniformserver.com/index.php/New_Users:_Problems_Section

The Uniform Server + Drupal 7 Installation Step-By-Step

Download the Uniform Server (version Coral 8.1.2) (Not the latest version; because Drupal needs PHP 5.3.10 and the latest is PHP 5.4.4 etc.)
http://sourceforge.net/projects/miniserver/files/Uniform%20Server/8.1.2-...

Double-click Coral_8_1_2.exe (the self-extracting file for Uniform Server, it will create a folder in the same directory called "UniServer").

Move the UniServer folder and its contents to where you want your application and new Drupal sites to reside:

(typically Users/(your name)/Sites/UniServer)
or E:/UniServer (on a RAM stick or SD card)

This page has step by step instructions for installing Drupal toolkit on windows operating system.

• Installing XAMPP
• Installing Drupal 6.x
• Installing Sun/Oracle Java 1.5 or higher
• Installing Apache Solr 1.3 or higher

Installing XAMPP

Apache HTTP, MySQL, and PHP (along with Perl or Python) are such a popular software stack that is often bundled together into XAMPP.

This installation guide assumes the user is using XAMPP for Apache, MySQL and PHP. Running the Drupal Toolkit on XAMPP distribution works well for developing environments, but is not best suited for production environments.

1. Navigate to http://sourceforge.net/projects/xampp/files/XAMPP%20Windows/1.7/
   Note: XAMPP 1.8 contains PHP 5.4.4 which is not currently supported so XAMPP 1.7 version has to be downloaded.
2. Click on “xampp-win32-1.7.0-installer.exe” to download the EXE file and follow the instructions.
3. Keep note of important directories used by XAMPP, which should be listed on the same web page, as this will be useful when configuring Apache, MySQL, and PHP

After installing XAMPP, check the status of each component by navigating to the URL: http://localhost/xampp

Note:
Troubleshooting Port already in use situation:

This is a summary of: #615474: Support for IIS 7 and applies to IIS 7 and IIS 7.5 with IIS Rewrite Module 2.0 module. Installation and configuration of the Boost 7.x and 6.x module itself are the same for IIS as any other webserver, with the exception of the following:

1. Make sure IIS Rewrite Module 2.0 is enabled. If you have IIS Rewrite, you need to upgrade for this to work. See http://www.iis.net/download/URLRewrite for info on this module. Note install of this module requires a server restart!

2. Add CONTENT_TYPE to allowed server variables. In the IIS Server Manager, go into URL Rewrite feature of the site. Click 'View Server Variables...' and add CONTENT_TYPE as an allowed server variable. If you don't do this you'll get a 500 error due no permissions to change the CONTENT_TYPE variable below. If you do not see the 'View Server Variables...' configuration option, you may have IIS Rewrite module 1.0 installed.

3. Add the rewrite rules. The attached files rewrite rules (boost_iis_7_with_IIS_rewrite_II_module.txt) should be added to your sites web.config list, before the Drupal clean URLs rule. The second attachment (default_web_config_with_boost_rules_in_it.txt) is the boost rules included in the default web.config that ships with drupal 7.

This is an alternative way to get Drush running on a Windows 7 system using the Cygwin environment. There is existing documentation on installing and running Drush using GnuWin tools and the native Windows shell at: http://drupal.org/node/594744