I actually just did the upgrade from Leopard to Snow Leopard, because I wanted to partition the drive to install Windows 7 on my Macbook. It's the first time I've used Bootcamp, and I had read several times on the forum that the new update for Bootcamp that made it play nicely with Win 7 was only supposedly updated for Snow Leopard, but not Leopard, which is why I upgraded to SL first (although I'm sure there are several people successfully using Leopard, Bootcamp, and Win 7).
The partitioning and install of Win 7 went flawlessly. I made sure to set my primary bootup to be MacOSX and not Windows, as it's the one I use 95% of the time anyway, and I just hold down the Option key when I want to boot into Windows.
As the previous poster suggested, print out the guide beforehand which is available when you bring up Boot Camp Assistant. I'm a techie, but I know it really came in handy for me. Also, the hardware drivers installed easily from the SL disc, once Windows was installed.
So far, everything has worked very well. Also I've been reminded of why I like the MacOS so much better than Windows -- not that Win 7 is bad -- it isn't, but I just like the MacOS a LOT better.