In addition to my answer below, I'd like to add point out that the Netbeans C++ edition is a very nice IDE too. At the time when I wrote my answer, I haven't considered looking at this because I only knew it from Java development, and for this I use Jetbrains IDEA. A bit later I tried Netbeans for a C++ project and it turned out to be very helpful and intuitive.
For the first part of your question about installing on a Win7 machine, please read on the official ubuntu. It is explained how you can create a dual system with Windows and Ubuntu.
For your second question: Yes, Ubuntu and Linux in general is excellent for C/C++ development. You have several choices if you want an IDE instead of a simple editor. I personally like Eclipse with C++ support, but you have several other choices
- Code::Blocks is a very nice C++ IDE
- Qt Creator which can be used for development in general and not only for Qt applications
- Anjuta is another one I tried long time ago which was quite nice..
Please find a long list of available IDE's here (although it's in German, you surly can read this).
Please note that especially Eclipse, Code::Blocks and QT Creator is not restricted to Ubuntu. You can try them in Windows too!