How to read and write Mac drives on Windows
For read only access you can try hfs explorer
You can install Apple bootcamp drivers (no official download links but you can find it on other sites) on a non-Apple machine. This will install HFS+ (the other name for Mac OS Extended) drivers for Windows.
Originally found on MacRumors forum, detailed instructions here
For those with Windows 7, drivers can be found using Apple KB: TS3172
http://support.apple.com/kb/ts3172
Seems like MediaFour MacDrive is the recommended one from various places. If anyone has any good and free alternatives or just other alternatives, I'd like to know about those though :)
Along with the ability to read and write to Mac disks and volumes, you can also create Mac disks for easy file transfers and backups. The built-in MacDrive Disk Manager gives you the power to partition, format, analyze and repair disks, while the newly revamped CD/DVD Creator allows you to burn Mac CDs and DVDs.