Ext2 Installable File System software gives you read write access to ext2 partition from windows (NT/2K/XP/2K3). It is available for free of cost.
Please refer FAQ for accessing ext3 partitions.
Configuration is very simple. Simply run the setup file and select the settings as prompted. At the end of setup, you have to specify the drive letter for ext2 partition(s). Once the setup is finished, you will find ext2 partition like any other drive in windows explorer.
Please see the following screenshots.
Disclaimer: Please use at your risk!