I wouldn't recommend using a dual boot, unless you are going to be gaming or otherwise.
I stopped doing the whole dual booting when I just couldn't be bothered switching from OS to OS via the offswitch. It sounds silly but it was too time consuming and if I wanted go play some windows games straight after coding I'd have to wait to reboot.
Firstly I tried
AndLinux (its similar to QEMU and uses the same VMWare technology), which is great as it will actually use the linux partition if you have a dual boot and the main distro you get with AndLinux when you set it up is ubuntu anyway (after they swapped from using debian). My advice for using this is to download POC 2.1, install that then download the prebeta and update the POC 2.1 to pre beta.
Don't just install the prebeta as I found X not to work and I think the main stuff that uses X is in the POC download.
I'm now using QEMU (well, will be again when I get the main pc up and running again). If you want to use that then I'd recommend getting
qemu Manager. It's a nice, and useful, gui frontend.
I do have a "how to" on my website for setting up qemu with qemu manager, but at the moment it is windows only, however, the first few steps you'll need to follow anyway since it's the setup of the virtual hard drive. Linux installations are pretty self explanatory, with one expection. The LILO bit.
I can explain that in a bit more detail when you've decided on what you want to use.
Oh and I know that you can install QEMU to a usb and use it that way but I don't know if this is possible with AndLinux.
If you get stuck with anything just PM me and I'm sure I can help.