Well, that is not Entirely true, you CAN see your linux partition in Windows. You can use programs like Explore2fs and many others. Do a search on Google. You can also find several on www.downloads.com
The problem is that the best program that used to be FREE is now trying to get you to fork over some cash, and the free version only lets you see 1GB of data, if your partition is bigger, you are out of luck. I won't even mention this programs name because it's lame to charge for the SAME software that you used to offer for free!
Enough of the ranting, anyway, if you have chosen to go with the newer EXT3, this is also supported with a few of the WIndows programs, I think Explore2fs is one of them.