Hi dark flame , some good sugestions previously , just a few of my own.
Run the Live Distro and get familiar with it . A GB of RAM is heaps .
Once you have decided to Install Ubuntu you need to be prepared . The biggest problem you may encounter by creating a Dual Boot setup is the Linux partitions overwriting some Windows system files as you haven't defragged the Drive . I defragged three times before hitting the Install button . Not just the Windows Defrag either . jkdefrag
is excellent for this . You can imagine the problem when you create a partition and some critical Windows files have been overwritten by it , not what anyone wants .
As far as Installing , from my personal experience I was guided through the process of creating partitions for Root , Home , and Page Swap File by the installer . Seemless operation , main consideration have a perfectly Defragmented Drive , and follow all instructions during the Install . I used 15 GB on the three partitions , no problem for what I wanted to do , which was take GNU/Linux onboard and get used to it before doing a complete Linux istallation . It's a steep learning curve , don't let anyone believe otherwise ! After some months you'll be very glad you did take the plunge