Yes, both work with Windows. And both are available online as downloads free of charge. Open Office is a heck of a suite for the price, $0. I've tinkered with it several times on several different machines. When creating new documents, spreadsheets, whatever, it's fine. I've encountered plenty of burps when bringing Office files into it, however. My personal preference remains MS Office, but if someone is on a tight budget, OO is very attractive.
As for Linux, Linspire has finally created a package that the average non-geek barely literate user can probably install and use. The installation process is straightforward and the interface is very Windows-like, enough so that performing typical tasks like browsing and office work is not that much of a transition.
MM
The problem isn't Open Office and its database compansion MySQL, its Microsoft Office's proprietary format. Its Microsoft not having open source standards that creates the compatibility issues to begin with. With a little bit of work you can still get OOO files and MySQL databases read by MSO. You'll lose a tad in the translation but not much. And the advantage of Linux is the software is free. Even the operating system is free but I paid to have an easy to use Linux and after trying out Mepis, I went back to Xandros. Downloading and installing new software from the net is a little difficult since one has to create icons on the desktop and put the program in the KDE programs list but its easy enough to learn. And running Linux with click and point is even easier than in Windows.