Bizarre, I set up dual boot on my machine with ubuntu/windows (mostly for WoW) and it worked perfectly first time, and I have never even messed with partitions before...
Seemed fairly logical, it had two partitions, one unformatted, one windows, then I selected the second one, it split into some crap (swap disk etc and main linux) then it just installed.
Then I just looked online for a quick script that mapped my windows disk in ubuntu, and I can use wine for all my windows applications, no problemo.
The only thing that was an issue was some episodes of an anime I had which were in real player format... not quite solved that yet.